bluuebunny/crossref_metadata_2025_split huggingface dataset:
Independent Loss of Immunogenic Proteins in
Mycobacterium ulcerans
Suggests Immune Evasion
Authors: Huber Charlotte A. , Ruf Marie-Thérèse , Pluschke Gerd , Käser Michael 
Published: February 2008

ABSTRACT

The highly immunogenic mycobacterial proteins ESAT-6, CFP-10, and HspX represent potential target antigens for the development of subunit vaccines and immunodiagnostic tests. Recently, the complete genome sequence revealed the absence of these coding sequences in
Mycobacterium ulcerans
, the causative agent of the emerging human disease Buruli ulcer. Genome reduction and the acquisition of a cytopathic and immunosuppressive macrolide toxin plasmid are regarded as crucial for the emergence of this pathogen from its environmental progenitor,
Mycobacterium marinum
. Earlier, we have shown the evolution of
M. ulcerans
into two distinct lineages. Here, we show that while the genome of
M. marinum
M contains two copies of the
esxB-esxA
gene cluster at different loci (designated MURD4 and MURD152), both copies are deleted from the genome of
M. ulcerans
strains belonging to the classical lineage. Members of the ancestral lineage instead retained some but disrupted most functional MURD4 or MURD152 copies, either by newly identified genomic insertion-deletion events or by conversions of functional genes to pseudogenes via point mutations. Thus, the
esxA
(ESAT-6),
esxB
(CFP-10), and
hspX
genes are located in hot-spot regions for genomic variation where functional disruption seems to be favored by selection pressure. Our detailed genomic analyses have identified a variety of independent genomic changes that have led to the loss of expression of functional ESAT-6, CFP-10, and HspX proteins. Loss of these immunodominant proteins helps the bacteria bypass the host's immunological response and may represent part of an ongoing adaptation of
M. ulcerans
to survival in host environments that are screened by immunological defense mechanisms.
Prophages in
Listeria monocytogenes
Contain Single-Nucleotide Polymorphisms That Differentiate Outbreak Clones within Epidemic Clones
Authors: Chen Yi , Knabel Stephen J. 
Published: February 2008

ABSTRACT

A fragment end ligation-mediated PCR strategy was used to analyze the AscI pulsed-field gel electrophoresis patterns of
Listeria monocytogenes
epidemic clone II (ECII), which led to the identification of single-nucleotide polymorphisms (SNPs) in prophage regions that differentiated the two ECII outbreak clones. SNPs in prophages that differentiated the outbreak clones of ECIII and -IV were also identified.
Comparison of Nine Commercially Available Assays for Quantification of Antibody Response to Hepatitis B Virus Surface Antigen
Authors: Huzly D. , Schenk T. , Jilg W. , Neumann-Haefelin D. 
Published: February 2008

ABSTRACT
Quantitative measurement of anti-HBs is used to evaluate the response to hepatitis B vaccination in health care workers and to optimize postexposure management. The different guidelines for hepatitis B vaccination and booster policy imply that the measurement of anti-HBs levels by different assays is accurate and consistent, yielding comparable quantitative results. We measured anti-HBs levels in 200 serum samples from patients and health care professionals by nine different anti-HBs assays and compared the quantitative results and the performance characteristics of the different test systems. The assay specificity ranged between 96.8 and 100% when sera from individuals without a vaccination history and with negative anti-HBc status were defined as true negatives. Sensitivity ranged between 93.5 and 100%. A high number of sera showed discrepancies between measurements by the different systems. The mean coefficient of variation between the different measurements was 47.1% (range, 15.0 to 201.0%), and the factors of multiplication ranged from 2.8 to 105. Hemolysis or lipemia did not seem to influence the measurement, and there was no difference between anti-HBc-positive and -negative individuals. The classical enzyme immunoassays tend to find lower anti-HBs levels than the automated systems, with higher values by the Abbott AXSYM assay. The serial dilution of the international standard preparation was measured accurately by most of the assays. In conclusion, the quantitative measurement of anti-HBs levels is not reliable, even though an international standard is used for the calibration of the systems. Some systems showed specific problems that should be addressed by the manufacturers.
Two Amino Acid Substitutions within the First External Loop of CCR5 Induce Human Immunodeficiency Virus-Blocking Antibodies in Mice and Chickens
Authors: Pastori Claudia , Clivio Alberto , Diomede Lorenzo , Consonni Roberto , De Mori Giacomo M. S. , Longhi Renato , Colombo Giorgio , Lopalco Lucia 
Published: February 2008

ABSTRACTAntibodies to the first loop (ECL1) of CCR5 have been identified in human immunodeficiency virus (HIV)-exposed uninfected individuals (ESN) and in HIV-positive nonprogressing subjects. Thus, these antibodies may confer resistance against HIV infection. To define which amino acids are involved in antibody binding to CCR5, we performed a peptide-scanning assay and studied the immunogenicity of peptides in animal models. A panel of synthetic peptides spanning the CCR5-ECL1 region and displaying glycine or alanine substitutions was assayed for antibody binding with a pool of natural anti-CCR5 antibodies. We used mice and chickens to study the immunogenicity of mutagenized peptide. Structural characterization by nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulations were performed to better understand the structural and conformational features of the mutagenized peptide. Amino acid substitutions in positions Ala95 and Ala96 (A95-A96) increased antibody-peptide binding compared to that of the wild-type peptide (Asp95-Phe96). The Ala95-96 peptide was shown to induce, in mice and chickens, antibodies displaying biological activity at very low concentrations. Strikingly, chicken antibodies to the Ala95-96 peptide specifically recognize human CCR5 molecules, downregulate receptors from lymphocytes, inhibit CCR5-dependent chemotaxis, and prevent infection by several R5 viruses, displaying 50% inhibitory concentrations of less than 3 ng/ml. NMR spectroscopy and molecular dynamics simulations proved the high flexibility of isolated epitopes and suggested that A95-A96substitutions determine a slightly higher tendency to generate helical conformations combined with a lower steric hindrance of the side chains in the peptides. These findings may be relevant to the induction of strong and efficient HIV-blocking antibodies.
Venezuelan Equine Encephalitis Virus Capsid Protein Inhibits Nuclear Import in Mammalian but Not in Mosquito Cells
Authors: Atasheva Svetlana , Garmashova Natalia , Frolov Ilya , Frolova Elena 
Published: February 2008

ABSTRACT
Venezuelan equine encephalitis virus (VEEV) represents a continuous public health threat in the United States. It has the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that replicating VEEV interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. VEEV capsid protein was found to play a critical role in this process, and its ∼35-amino-acid-long peptide, fused with green fluorescent protein, functioned as efficiently as did the entire capsid. We detected a significant fraction of VEEV capsid associated with nuclear envelope, which suggested that this protein might regulate nucleocytoplasmic trafficking. In this study, we demonstrate that VEEV capsid and its N-terminal sequence efficiently inhibit multiple receptor-mediated nuclear import pathways but have no effect on the passive diffusion of small proteins. The capsid protein of the Old World alphavirus Sindbis virus and the VEEV capsid, with a previously defined frameshift mutation, were found to have no detectable effect on nuclear import. Importantly, the VEEV capsid did not noticeably interfere with nuclear import in mosquito cells, and this might play a critical role in the ability of the virus to develop a persistent, life-long infection in mosquito vectors. These findings demonstrate a new aspect of VEEV-host cell interactions, and the results of this study are likely applicable to other New World alphaviruses, such as eastern and western equine encephalitis viruses.
Origin of the Springtime Westerly Bias in Equatorial Atlantic Surface Winds in the Community Atmosphere Model Version 3 (CAM3) Simulation
Authors: Chang Ching-Yee , Nigam Sumant , Carton James A. 
Published: February 2008

Abstract
This study makes the case that westerly bias in the surface winds of the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, version 3 (CAM3), over the equatorial Atlantic in boreal spring has its origin in the rainfall (diabatic heating) bias over the tropical South American continent. The case is made by examination of the spatiotemporal evolution of regional precipitation and wind biases and by dynamical diagnoses of the westerly wind bias from experiments with a steady, linearized dynamical core of an atmospheric general circulation model. Diagnostic modeling indicates that underestimating rainfall over the eastern Amazon region can lead to the westerly bias in equatorial Atlantic surface winds.
The study suggests that efforts to reduce coupled model biases, especially seasonal ones, must target continental biases, even in the deep tropics where ocean–atmosphere interaction generally rules.
Platelet-derived CD154 enables T-cell priming and protection against Listeria monocytogenes challenge
Authors: Elzey Bennett D. , Schmidt Nathan W. , Crist Scott A. , Kresowik Timothy P. , Harty John T. , Nieswandt Bernhard , Ratliff Timothy L. 
Published: February 2008

AbstractCollagen exposure in tissue activates platelets, initiates wound healing, and modulates adaptive immunity. In this report, data are presented to demonstrate a requirement for platelet-derived CD154 for both collagen-induced augmentation of T-cell immunity and induction of pro-tective immunity to Listeria challenge. Specifically, we demonstrate that Ad5 encoding the membrane-bound form of ovalbumin (Ad5-mOVA) delivered in collagen induces higher ovalbumin-specific cytotoxic T lymphocyte (CTL) activity in a dose-dependent manner compared with Ad5-mOVA delivered in PBS. Increased CTL activity was dependent on the ability of platelets to respond to collagen and to express CD154. Furthermore, mice immunized with low-dose Ad5-mOVA in collagen were able to control a challenge of Listeria monocytogenes recombinant for ovalbumin expression (Lm-OVA), whereas mice immunized with low-dose Ad5-mOVA in PBS were not. These data indicate that in a physiologic setting that mimics wounding, platelets perform a sentinel function when antigen dose is too low to provoke an efficient immune response, and can enhance the generation of antigen-specific CD8 T cells that are functionally relevant to the host.
Intracellular survival and vascular cell-to-cell transmission of Porphyromonas gingivalis
Authors: Li Ling , Michel Raynald , Cohen Joshua , DeCarlo Arthur , Kozarov Emil 
Published: February 2008

Abstract

Background

Porphyromonas gingivalis is associated with periodontal disease and invades different cell types including epithelial, endothelial and smooth muscle cells. In addition to P. gingivalis DNA, we have previously identified live invasive bacteria in atheromatous tissue. However, the mechanism of persistence of this organism in vascular tissues remains unclear. Therefore, the objective of this study was to analyze the ability of intracellular P. gingivalis to persist for extended periods of time, transmit to and possibly replicate in different cell types.

Results
Using antibiotic protection assays, immunofluorescent and laser confocal microscopy, we found that after a prolonged intracellular phase, while P. gingivalis can still be detected by immunostaining, the intracellular organisms lose their ability to be recovered in vitro. Surprisingly however, intracellular P. gingivalis could be recovered in vitro upon co incubation with fresh vascular host cells. We then demonstrated that the organism was able to exit the initially infected host cells, then enter and multiply in new host cells. Further, we found that cell-to-cell contact increased the transmission rate but was not required for transmission. Finally, we found that the invasion of new host cells allowed P. gingivalis to increase its numbers.

Conclusion
Our results suggest that the persistence of vascular tissue-embedded P. gingivalis is due to its ability to transmit among different cell types. This is the first communication demonstrating the intercellular transmission as a likely mechanism converting latent intracellular bacteria from state of dormancy to a viable state allowing for persistence of an inflammatory pathogen in vascular tissue.
Epidemiology and outcomes of community-onset methicillin-susceptible Staphylococcus aureusbacteraemia in a university hospital in Singapore
Authors: Chia Jonathan Wei-Zhong , Hsu Li-Yang , Chai Louis Yi-Ann , Tambyah Paul Ananth 
Published: February 2008

Abstract

Background
Methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia remains a condition associated with considerable morbidity and mortality worldwide. It is a common but little-studied problem outside of Europe and North America.

Methods
A single-centre retrospective case series profiling all patients with community onset-MSSA bacteraemia presenting between March 2005 and February 2006 to a tertiary acute-care university hospital in Singapore. In addition to epidemiological and clinical data collection, risk factors for complicated bacteremia and attributable mortality were analysed.

Results
A total of 100 patients met the case definition. Patients were more likely to be male (65%) and below 65 years of age (69%). Seventeen patients were intravenous drug abusers, while 38 had diabetes mellitus. There were 18 cases of endocarditis, with 11 occurring in intravenous buprenorphine abusers. Attributable mortality was 11%, and 46% of patients developed complicated bacteremia. On multivariate analysis, age > 65 years and presence of chronic pulmonary disease were the only significant risk factors for the former, while valvular heart disease was a significant risk factor for the latter.

Conclusion
MSSA bacteraemia is associated with a significant risk of serious complications in Singapore. Other Asian cities should be alert to the risk factors for adverse outcomes for this important cause of morbidity and mortality.
Finding exonic islands in a sea of non-coding sequence: splicing related constraints on protein composition and evolution are common in intron-rich genomes
Authors: Warnecke Tobias , Parmley Joanna L , Hurst Laurence D 
Published: February 2008

Abstract
Background
In mammals, splice-regulatory domains impose marked trends on the relative abundance of certain amino acids near exon-intron boundaries. Is this a mammalian particularity or symptomatic of exonic splicing regulation across taxa? Are such trends more common in species that a priori have a harder time identifying exon ends, that is, those with pre-mRNA rich in intronic sequence? We address these questions surveying exon composition in a sample of phylogenetically diverse genomes.

Results
Biased amino acid usage near exon-intron boundaries is common throughout the metazoa but not restricted to the metazoa. There is extensive cross-species concordance as to which amino acids are affected, and reduced/elevated abundances are well predicted by knowledge of splice enhancers. Species expected to rely on exon definition for splicing, that is, those with a higher ratio of intronic to coding sequence, more introns per gene and longer introns, exhibit more amino acid skews. Notably, this includes the intron-rich basidiomycete Cryptococcus neoformans, which, unlike intron-poor ascomycetes (Schizosaccharomyces pombe, Saccharomyces cerevisiae), exhibits compositional biases reminiscent of the metazoa. Strikingly, 5 prime ends of nematode exons deviate radically from normality: amino acids strongly preferred near boundaries are strongly avoided in other species, and vice versa. This we suggest is a measure to avoid attracting trans-splicing machinery.

Conclusion
Constraints on amino acid composition near exon-intron boundaries are phylogenetically widespread and characteristic of species where exon localization should be problematic. That compositional biases accord with sequence preferences of splice-regulatory proteins and are absent in ascomycetes is consistent with selection on exonic splicing regulation.
Wie volkstümlich ist die byzantinische Volksliteratur?
Authors: Cupane Carolina 
Published: February 2008

Abstract
Gegenstand unserer Frage und der Überlegungen dazu ist ein Corpus von Texten, die grosso modo zwischen dem XIV. und dem XV. Jahrhundert enstanden sind, in jener Epoche also, die nach dem Namen der regierenden Dynastie auch als Palaiologenzeit bezeichnet wird. In Gegensatz zur sonstigen byzantinischen Literatur, die sich antikisierend am attischen Griechisch orientierte, sind sie in einer Sprachform verfaßt, die viele Ähnlichkeiten mit dem modernen neugriechischen Idiom aufweist. Diese neue Texte kennzeichnet bei aller inhaltlichen Vielfalt – abenteuerliche, heldenhafte, romanhafte Themen werden gleich satirischen, didaktischen und paränetischen behandelt – eine strenge formale Einheitlicheit insofern, als sie beinahe alle in dem auch für die neugriechische (Volks)dichtung charakteristischen Versmaß, dem ungereimten, von den Byzantinern selbst πολιτιϰὸς στίχος genannten Fünfzehnsilber verfaßt sind und eine mehr oder weniger starke Formelhaftigkeit in der poetischen Diktion aufweisen. Darüber hinaus runden weitere äußerliche Eigenschaften, etwa die instabile, variantenreiche und sehr spät einsetzende handschriftliche Überlieferung oder die durchgehende Anonymität der Werke, die homogene Erscheinung des volksprachlichen Literaturcorpus ab.
Die Redactio Accursiana der Vita Aesopi: Ein Werk des Maximos Planudes
Authors: Karla Grammatiki 
Published: February 2008

Abstract
Bei der Vita Aesopi handelt es sich um eine Erzählung der Abenteuer Äsops bis zu seinem Tod in Delphi. Das Original, das vermutlich zu Beginn unserer Zeitrechnung ver faßt wurde, ist verloren, wurde aber in mehreren griechischen Fassungen überliefert.
When did Michael Psellus die? The evidence of the Dioptra
Authors: Karpozilos Apostolos 
Published: February 2008

Abstract
The last years of Michael Psellos' life are clouded in obscurity. He was certainly active at the court of his student Michael VII (1071–1078), but when Nikephoritzes, the logothetes tou dromou, became imperial advisor (Attaleiates, Historia, 200,12ff) he practically disappeared from the scene. One of the last chronological references found in his Chronographia is the death of Crispinus in 1075 (VII, b 39, 3–4). In that year he also wrote a description of the “usual miracle” which occurred regularly in the church of Blachernai and somewhat later a funeral oration for Patriarch Ioannes Xiphilinos. Among his writings survives another funeral oration which he dedicated to the young Andronikos Doukas. This work is transmitted only in part by cod. Parisinus gr. 1182 and is dated in 1076. From that point on, practically nothing is known about his subsequent life.
Zu jambischen Versen an einer Mauer in Konstantinopel
Authors: Rhoby Andreas 
Published: February 2008

Abstract
Theodosios Zygomalas, berühmter Protonotar der Großen Kirche in Konstantinopel, erwähnt in einem Brief vom 7. April 1581 an den deutschen Gelehrten und Philhellenen Martin Crusius jambische Verse über Athen, die er an einer Mauer gelesen hat.
Zur Datierung von Themistius or. 4
Authors: Wintjes Jorit 
Published: February 2008

Abstract
Über die Datierung der vierten Rede des Themistius sowie ihr zeitliches Verhältnis zur dritten Rede besteht in der Forschung keine Einigkeit. Verschiedene Termine zwischen dem Winter 355/356 und dem Winter 358/359 sind dabei vorgeschlagen worden. An der nunmehr fast einhundert Jahre alten Diskussion fällt auf, daß die jeweils ins Feld geführten Argumente nahezu ausschließlich auf den Text der Rede bezogen sind. Weitgehend unbeachtet geblieben ist hingegen der Zusammenhang der Datierungsfrage von or. 4 mit der Antiochiareise des Themistius im Jahre 356 und den hierzu gehörigen Libaniusbriefen, darunter insbesondere ep. 551. Im Folgenden soll daher versucht werden, anhand der Frage, wo sich Themistius zwischen dem Sommer 356 und dem Sommer 357 aufgehalten hat, Licht in die Datierungsproblematik zu bringen.
Georgij Avvakumov, Die Entstehung des Unionsgedankens. Die lateinische Theologie des Hochmittelalters in der Auseinandersetzung mit dem Ritus der Ostkirche
Authors: Barmin Alexander 
Published: February 2008

Abstract
Das Buch besteht aus zwei Teilen, deren der erste den griechisch-lateinsichen Streitigkeiten des 11.–13. Jahrhunderts gewidmet ist, während im zweiten die lateinischen Zugänge zur Eigenart der Ostkirche aus derselben Zeit dargestellt sind.
Axel Bayer, Spaltung der Christenheit. Das sogenannte Morgendländische Schisma von 1054. [Beihefte zum Archiv für Kulturgeschichte, 53.]
Authors: Tinnefeld Franz 
Published: February 2008

Abstract
Das wesentliche Ergebnis dieser an der Universität Köln von Odilo Engels betreuten und für den Druck leicht überarbeiteten Dissertation ist in folgendem Zitat (S. 203) zusammengefaßt: „Für das Jahr 1054 ist ungeachtet der gegenseitigen Bannsprüche kein Schisma zwischen der römischen und der konstantinopolitanischen Kirche zu konstatieren. … Auch wenn der Dissens in den Jahrzehnten nach 1054 nicht zu unterschätzen ist, hat sich erst infolge des ersten Kreuzzuges (1096–1099) der Konflikt entscheidend verschärft.“ Daß von einem Schisma im umfassenden Sinne einer Kirchenspaltung im Jahr 1054 noch nicht die Rede sein kann, wurde zwar auch zuvor schon öfters beobachtet, aber eine allgemeine Akzeptanz dieser Erkenntnis ließ bislang auf sich warten, wie auch die Übersicht über die verschiedenen Bewertungen des Ereignisses in der Sekundärliteratur (S. 2f.) zeigt. Bayer kann mit seiner umfassenden Analyse der Beziehungen zwischen den Kirchen Roms und Konstantinopels im Umfeld des Jahres 1054 überzeugender als bisher zeigen, daß in diesem Jahr nur ein weiterer wichtiger Schritt auf das Schisma hin erfolgte. Eine vorsichtigere Formulierung wie „das Zerwürfnis von 1054“ dürfte daher eher die Sache treffen. Erst seit den Kreuzzügen verschlechterte sich das Klima zwischen beiden Kirchen bis zu einem Bruch, der sich in der Folgezeit, vor allem nach dem fatalen „Vierten Kreuzzug“, noch weiter vertiefen sollte.