bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quinone Reduction by the Na+-Translocating NADH Dehydrogenase Promotes Extracellular Superoxide Production inVibrio cholerae
Authors: Lin Po-Chi , Türk Karin , Häse Claudia C. , Fritz Günter , Steuber Julia 
Published: February 2007

ABSTRACTThe pathogenicity ofVibrio choleraeis influenced by sodium ions which are actively extruded from the cell by the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). To study the function of the Na+-NQR in the respiratory chain ofV. cholerae, we examined the formation of organic radicals and superoxide in a wild-type strain and a mutant strain lacking the Na+-NQR. Upon reduction with NADH, an organic radical was detected in native membranes by electron paramagnetic resonance spectroscopy which was assigned to ubisemiquinones generated by the Na+-NQR. The radical concentration increased from 0.2 mM at 0.08 mM Na+to 0.4 mM at 14.7 mM Na+, indicating that the concentration of the coupling cation influences the redox state of the quinone pool inV. choleraemembranes. During respiration,V. choleraecells produced extracellular superoxide with a specific activity of 10.2 nmol min−1mg−1in the wild type compared to 3.1 nmol min−1mg−1in the NQR deletion strain. Raising the Na+concentration from 0.1 to 5 mM increased the rate of superoxide formation in the wild-typeV. choleraestrain by at least 70%. Rates of respiratory H2O2formation by wild-typeV. choleraecells (30.9 nmol min−1mg−1) were threefold higher than rates observed with the mutant strain lacking the Na+-NQR (9.7 nmol min−1mg−1). Our study shows that environmental Na+could stimulate ubisemiquinone formation by the Na+-NQR and hereby enhance the production of reactive oxygen species formed during the autoxidation of reduced quinones.
Role of EAL-Containing Proteins in Multicellular Behavior ofSalmonella entericaSerovar Typhimurium
Authors: Simm Roger , Lusch Astrid , Kader Abdul , Andersson Mats , Römling Ute 
Published: February 2007

ABSTRACTGGDEF and EAL domain proteins are involved in turnover of the novel secondary messenger cyclic di(3′→5′)-guanylic acid (c-di-GMP) in many bacteria. The rdar morphotype, a multicellular behavior ofSalmonella entericaserovar Typhimurium characterized by the expression of the extracellular matrix components cellulose and curli fimbriae is controlled by c-di-GMP. In this work the roles of the EAL and GGDEF-EAL domain proteins on rdar morphotype development were investigated. Knockout of four of 15 EAL and GGDEF-EAL domain proteins upregulated rdar morphotype expression and expression of CsgD, the central regulator of the rdar morphotype, and partially downregulated c-di-GMP concentrations. More-detailed analysis showed that the EAL domain protein STM4264 and the GGDEF-EAL domain protein STM1703, which highly downregulated the rdar morphotype, have overlapping yet distinct functions. Another subset of EAL and GGDEF-EAL domain proteins influenced multicellular behavior in liquid culture and flagellum-mediated motility. Consequently, this work has shown that several EAL and GGDEF-EAL domain proteins, which act as phosphodiesterases, play a determinative role in the expression level of multicellular behavior ofSalmonella entericaserovar Typhimurium.
Analysis of Temporal Gene Expression duringBacillus subtilisSpore Germination and Outgrowth
Authors: Keijser Bart J. F. , Ter Beek Alex , Rauwerda Han , Schuren Frank , Montijn Roy , van der Spek Hans , Brul Stanley 
Published: February 2007

ABSTRACTBacillus subtilisforms dormant spores upon nutrient depletion. Under favorable environmental conditions, the spore breaks its dormancy and resumes growth in a process called spore germination and outgrowth. To elucidate the physiological processes that occur during the transition of the dormant spore to an actively growing vegetative cell, we studied this process in a time-dependent manner by a combination of microscopy, analysis of extracellular metabolites, and a genome-wide analysis of transcription. The results indicate the presence of abundant levels of late sporulation transcripts in dormant spores. In addition, the results suggest the existence of a complex and well-regulated spore outgrowth program, involving the temporal expression of at least 30% of theB. subtilisgenome.
Characterization of a Novel Two-Partner Secretion System in
Escherichia coli
O157:H7
Authors: Choi Peter S. , Dawson Ashley J. , Bernstein Harris D. 
Published: February 2007

ABSTRACT

Gram-negative bacteria contain multiple secretion pathways that facilitate the translocation of proteins across the outer membrane. The two-partner secretion (TPS) system is composed of two essential components, a secreted exoprotein and a pore-forming β barrel protein that is thought to transport the exoprotein across the outer membrane. A putative TPS system was previously described in the annotation of the genome of
Escherichia coli
O157:H7 strain EDL933. We found that the two components of this system, which we designate OtpA and OtpB, are not predicted to belong to either of the two major subtypes of TPS systems (hemolysins and adhesins) based on their sequences. Nevertheless, we obtained direct evidence that OtpA and OtpB constitute a bona fide TPS system. We found that secretion of OtpA into the extracellular environment in
E. coli
O157:H7 requires OtpB and that when OtpA was produced in an
E. coli
K-12 strain, its secretion was strictly dependent on the production of OtpB. Furthermore, using OtpA/OtpB as a model system, we show that protein secretion via the TPS pathway is extremely rapid.
Biofilms Formed by Nontypeable
Haemophilus influenzae
In Vivo Contain both Double-Stranded DNA and Type IV Pilin Protein
Authors: Jurcisek Joseph A. , Bakaletz Lauren O. 
Published: February 2007

ABSTRACT

Nontypeable
Haemophilus influenzae
(NTHI) strains are members of the normal human nasopharyngeal flora, as well as frequent opportunistic pathogens of both the upper and lower respiratory tracts. Recently, it has been shown that NTHI can form biofilms both in vitro and in vivo. NTHI strains within in vitro-formed biofilms differentially express both epitopes of lipooligosaccharide (LOS) and the outer membrane proteins P2, P5, and P6, whereas those generated either in a 96-well plate assay in vitro or in a mammalian host have been shown to incorporate a specific glycoform of sialylated LOS within the biofilm matrix. While DNA has been identified as a key component of the biofilm matrix formed in vitro by several bacterial pathogens, here we demonstrate for the first time that in addition to sialylated LOS, the biofilm formed by NTHI in vivo contains both type IV pilin protein and a significant amount of double-stranded DNA. The DNA appeared to be arranged in a dense interlaced meshwork of fine strands as well as in individual thicker “ropes” that span water channels, suggesting that DNA could be imparting structural stability to the biofilm produced by NTHI in vivo. The presence of type IV pilin protein both appearing as small aggregates within the biofilm matrix and tracking along DNA strands supports our observations which showed that type IV pili are expressed by NTHI during experimental otitis media when these bacteria form a biofilm in the middle ear space.
Mutations Blocking Side Chain Assembly, Polymerization, or Transport of a Wzy-DependentStreptococcus pneumoniaeCapsule Are Lethal in the Absence of Suppressor Mutations and Can Affect Polymer Transfer to the Cell Wall
Authors: Xayarath Bobbi , Yother Janet 
Published: February 2007

ABSTRACTExtracellular polysaccharides of many bacteria are synthesized by the Wzy polymerase-dependent mechanism, where long-chain polymers are assembled from undecaprenyl-phosphate-linked repeat units on the outer face of the cytoplasmic membrane. In gram-positive bacteria, Wzy-dependent capsules remain largely cell associated via membrane and peptidoglycan linkages. Like many Wzy-dependent capsules, theStreptococcus pneumoniaeserotype 2 capsule is branched. In this study, we found that deletions ofcps2K,cps2J, orcps2H, which encode a UDP-glucose dehydrogenase necessary for side chain synthesis, the putative Wzx transporter (flippase), and the putative Wzy polymerase, respectively, were obtained only in the presence of suppressor mutations. Most of the suppressor mutations were incps2E, which encodes the initiating glycosyltransferase for capsule synthesis. Thecps2Kmutants containing the suppressor mutations produced low levels of high-molecular-weight polymer that was detected only in membrane fractions.cps2K-repaired mutants exhibited only modest increases in capsule production due to the effect of the secondary mutation, but capsule was detectable in both membrane and cell wall fractions. Lethality of thecps2K,cps2J, andcps2Hmutations was likely due to sequestration of undecaprenyl-phosphate in the capsule pathway and either preclusion of its turnover for utilization in essential pathways or destabilization of the membrane due to an accumulation of lipid-linked intermediates. The results demonstrate that proper polymer assembly requires not only a functional transporter and polymerase but also complete repeat units. A central role for the initiating glycosyltransferase in controlling capsule synthesis is also suggested.
Separation of Chromosome Termini during Sporulation of
Bacillus subtilis
Depends on SpoIIIE
Authors: Bogush Marina , Xenopoulos Panagiotis , Piggot Patrick J. 
Published: February 2007

ABSTRACT

Bacillus subtilis
undergoes a highly distinctive division during spore formation. It yields two unequal cells, the mother cell and the prespore, and septum formation is completed before the origin-distal 70% of the chromosome has entered the smaller prespore. The mother cell subsequently engulfs the prespore. Two different probes were used to study the behavior of the terminus (
ter
) region of the chromosome during spore formation. Only one
ter
region was observed at the time of sporulation division. A second
ter
region, indicative of chromosome separation, was not distinguishable until engulfment was nearing completion, when one was in the mother cell and the other in the prespore. Separation of the two
ter
regions depended on the DNA translocase SpoIIIE. It is concluded that SpoIIIE is required during spore formation for chromosome separation as well as for translocation; SpoIIIE is not required for separation during vegetative growth.
Spindle proteins Aurora A and BUB1B, but not Mad2, are aberrantly expressed in dysplastic mucosa of patients with longstanding ulcerative colitis
Authors: Burum-Auensen E , DeAngelis P M , Schjølberg A R , Røislien Jo , Andersen S N , Clausen O P F 
Published: February 2007

Background:Long term ulcerative colitis (UC) increases the risk of colorectal cancer (CRC). DNA aneuploidy is a common feature of both dysplastic and non-dysplastic colonic epithelia from patients with longstanding UC, and is regarded as an early sign of possible malignant transformation. The spindle proteins Aurora A, BUB1B and Mad2 have been implicated as contributors to aneuploidy and carcinogenesis.Aims:To investigate the role of these spindle proteins in relation to DNA aneuploidy and during the progressive morphological changes in ulcerative colitis associated colorectal cancer (UCCRC).Methods:Tissue microarrays were made from 31 colectomy specimens from patients with longstanding UC. Expression of Aurora A, BUB1B and Mad2 was investigated by immunohistochemistry and their relation to ploidy status, mucosal morphology and Ki67 levels was explored.Results:Expression of Aurora A and BUB1B was significantly associated with the progressive morphological changes of UCCRC. In the progression from non-dysplastic to dysplastic mucosa, Aurora A expression decreased while BUB1B expression increased. There was an increasing incidence of aneuploidy with progression towards cancer; expression of all spindle proteins was associated with the level of Ki67 but not with aneuploidy.Conclusion:Due to the significant differences in Aurora A and BUB1B expression in dysplastic compared non-dysplastic mucosa, these proteins may serve as putative biological markers for the progressive morphological changes in UC associated carcinogenesis. The close relationship to Ki67 levels reflect that spindle proteins are expressed in tissues with a high proliferative rate; a role for these proteins in the development of aneuploidy was not found.
HER2 testing in the UK: consensus from a national consultation
Authors: Dowsett Mitch , Hanby A M , Laing R , Walker R 
Published: February 2007

Objective:To gain an understanding of current attitudes among oncologists and pathologists to prospective HER2 testing in breast cancer and to gauge whether a national consensus exists regarding extent and quality of testing.Design:Qualitative study, with semi-quantitative components, using emailed questionnaires and open-ended discussion documents.Participants:186 relevant specialists, including 76 breast oncologists and 99 pathologists, representing all but three of the UK cancer networks.Results:A strong consensus was seen in favour of universal, non-selective testing for HER2 at the point of breast cancer diagnosis. Similarly, an overwhelming majority of participants agreed that, to optimise the quality of test results, all laboratories undertaking HER2 testing should be CPA-accredited, participate in the recognised national external quality assessment scheme (UK NEQAS), and carry out a formal annual audit of its testing service. A further recommendation that testing be restricted to laboratories undertaking a minimum 250 tests per annum for immunohistochemistry and 100 tests per annum for in situ hybridisation techniques met with majority support. However, this was not a clear consensus; a significant minority of participants favoured continued use of local services falling short of these criteria.Conclusion:This study was successful in gauging national specialist opinion regarding the extent and quality assurance of HER2 testing in the UK.
The Gospel of Barnabas, the Diatessaron, and Method
Authors: Schmid Ulrich , den Hollander August 
Published: February 2007

AbstractSince the beginning of the 20th century research aiming at reconstructing Tatian's lost Gospel harmony Diatessaron utilizes a growing number of late 13-15 c. texts extant in various Western vernaculars for this purpose. As the most recent example Jan Joosten introduced the so-called Gospel of Barnabas, a composition perhaps as late as the 16th or 17th century as a potential source for readings of the Diatessaron (2nd c.). With special emphasis on methodological issues, this essay offers a detailed critique of Joosten's analysis as well as a general critique of that type of research as carried out by other scholars in the past.
A Note on the Status of Origen's De Principiis in English
Authors: Rombs Ronnie 
Published: February 2007

AbstractThe standard English translation of Origen's De principiis, translated by G.W. Butterworth and published in 1936, is based upon the earlier critical edition of Paul Koetschau. Origen's text survives through the Latin translation of Rufinus, a version that Koetschau fundamentally distrusted: Rufinus had admittedly expurgated Origen's text and could not, accordingly, be trusted. Hence the job of the editor and translator was judged to be the reestablishment—as far as was possible—of Origen's original text. Such suspicion of the text led to, among other problems, the awkward printing of parallel Greek and Latin passages in columns in Butterworth's English edition. Greek fragments and Origenistic material—that is to say, passages that were not direct quotations of De principiis, nor even directly Origen's—were inserted into Koetschau's text based upon presumed doctrinal parallels between those fragments and Origen's 'authentic' thought.We cannot reconstruct the Greek text; what we have inherited for better or worse is Rufinus's Latin translation of Peri archôn, a text that the more recent scholarship of G. Bardy and others have significantly rehabilitated confidence in. With the notable exception of English, translations of De principiis have been made in French, Italian and German, based upon more recent and more balanced critical editions. The author proposes a new English translation of Rufinus's Latin text based upon the critical edition of Henri Crouzel and Manlio Simonetti, published in the Sources Chrétiennes series.
Anastasius I and Innocent I: Reconsidering the Evidence of Jerome
Authors: Dunn Geoffrey 
Published: February 2007

AbstractThe comment of Jerome in his letter to Demetrias (Epistula 130) that Innocent I, bishop of Rome from 402 to 417, was the son of his predecessor Anastasius I has been taken at face value by a number of commentators and has been repeated, often without reference to sources, on any number of Internet web sites. The fact that Liber Pontificialis offers a different parentage for Innocent is often ignored. This paper seeks to reconcile and evaluate the two accounts. The argument advanced here is that in Jerome's highly rhetorical letter the reference is to be understood metaphorically and not literally, given that the use of familial terms of address was common in early Christian letters to indicate a hierarchical rather than a biological relationship. Jerome was asserting that Innocent had been a deacon of Rome under Anastasius. Even beyond this common usage, in this letter such metaphor was part of a rhetorical strategy by which he sought to persuade a powerful Roman senatorial family to back his anti-Pelagian campaign and to use their influence on Innocent to do the same.
Socratic Dialogue or Courtroom Debate? Judicial Rhetoric and Stasis Theory in the Dialogue on the Life of St. John Chrysostom
Authors: Katos Demetrios 
Published: February 2007

AbstractThe Dialogue on the Life of St. John Chrysostom (written c. 407/8) has long puzzled modern readers on account of its choice of the dialogue form and its bewildering organization. Its attribution to Palladius of Helenopolis (c. 363-430) has often been contested, too. This article proposes that the dialogue form was chosen to convey the spirit of advocacy that lies at the heart of this composition, and then demonstrates that various compositional decisions can be explained by principles of judicial rhetoric and late antique stasis (issue) theory, particularly those of Hermogenes of Tarsus (c. 160-230) whose rhetorical handbook had become important by the fourth and fifth centuries in rhetorical training. These elements suggest that the author of the Dialogue was well trained in judicial rhetoric and that he composed this work primarily to make a case for John's restoration to the diptychs as bishop, rather than as a biographical or historical record as previously assumed. The influence of stasis theory in this composition also confirms the continued importance of judicial rhetoric in the late empire and bolsters the case for the authorship of Palladius, who had been commissioned by John to investigate charges raised against Antoninus of Ephesus and by Innocent of Rome to petition Arcadius for John's restoration.
'Microstructure' in Greek Tragedy: From Bad to Worse—Wrong Guesses in Euripidean Stichomythia (Including a Comparison with Aeschylus and Sophocles): Part I. Description and Analysis)
Authors:   Dubischar
Published: February 2007

AbstractThis publication is subdivided into two major parts. Part I brings to attention and analyzes a hitherto undiscovered set-piece of Euripidean stichomythic dialogue. This dialogue occurs most regularly and most powerfully in the Euripidean tragedies up to the year 415, in situations when bad news is revealed to an unknowing character. This small pattern—for which film theory offers the suitable term 'microstructure'—consists of one speaker's false guess (or guesses) before he (or she) learns the truth. In Part II of this contribution the earlier findings are set within a larger context by means of comparison, by tentatively tracing the pattern's origin and determining what Euripides' specific achievement may be, and, finally, by pointing out fundamental similarities between the production of ancient Greek tragedy and the production of modern popular film.
Ctesias of Cnidus, a Reappraisal
Authors: Stronk Jan 
Published: February 2007

AbstractThe works of Ctesias of Cnidus have frequently been regarded as second rate at best. His reliability as a historian has been seriously questioned in particular, not only by Felix Jacoby and many historians after him, but also by authors in antiquity. Doubts were especially raised about Ctesias' Indica, but also the trustworthiness of his Persica was—and still is—considered dubious. This verdict appears to be unfair, for two reasons. The first is that hardly anything that can be attributed directly to Ctesias has survived: the overwhelming majority of material ascribed to Ctesias has been transmitted by other authors, who used their source not necessarily with proper care. The second is to be found in Demetrius' On Style: here a new perspective on Ctesias is offered. It shows that we should no longer regard Ctesias primarily as a historian, but as a forerunner of a new literary genre (culminating in the classical novel) mixing historical fact with fictitious elements. It is only because of the lack of a proper word in antiquity to describe this genre that the term 'history' was applied to his work as well. It would confuse many generations of historians and deny Ctesias his proper place in Greek literary history.
Strategic Differences: Seneca and Plutarch on Controlling Anger
Authors:   van Hoof
Published: February 2007

AbstractIn a span of less than a century, Seneca and Plutarch both wrote works arguing against anger. This article studies these texts as speech acts, that is, as discourses through which the authors, by various means, seek to produce a certain effect in their readers. The comparison of several parallel passages from Seneca's On Anger and Plutarch's On the Control of Anger with regard to genre, philosophical technicality, rhetorical strategies, and specific argumentation brings to the fore how Seneca, in his plea for the eradication of anger, instills a concept of virtue substantially different from what most Romans would be familiar with, whereas Plutarch promotes the control of anger as an important part of the way a gentleman presents himself in a civilised society.
The Role of the Ekphrasis in Plot Development: The Painting of Europa and the Bull in Achilles Tatius' Leucippe and Clitophon
Authors: Reeves Bridget 
Published: February 2007

AbstractThis article examines the effectiveness of the ekphrasis of Europa and the bull which is placed at the beginning of Achilles Tatius' Leucippe and Clitophon, in order to shed light on its role in the development and progression of the plot in the novel. Although some critics have discussed the ekphrasis' anticipatory effectiveness with regard to the main characters, Leucippe and Clitophon, nevertheless much more can be said about the function of the set-piece description as a tool for foreshadowing events which transpire for the hero and heroine. In addition, this article demonstrates that the ekphrasis depicting Europa and the bull is not limited to prefiguring the actions of the main narrative as previously believed, but seems to act as a template for the plots of all of the mini-episodes that occur in the novel. By way of a table at the end of this article I present the template and the features common to the Europa-ekphrasis and to each of the mini-episodes in order to illuminate further the set-piece description's anticipatory effectiveness.