bluuebunny/crossref_metadata_2025_split huggingface dataset:
Roles of the Extraintestinal Pathogenic
Escherichia coli
ZnuACB and ZupT Zinc Transporters during Urinary Tract Infection
Authors: Sabri Mourad , Houle Sébastien , Dozois Charles M. 
Published: December 2008

ABSTRACT

Roles of the ZnuACB and ZupT transporters were assessed in
Escherichia coli
K-12 and uropathogenic
E. coli
(UPEC) CFT073. K-12 and CFT073 Δ
znu
Δ
zupT
mutants demonstrated decreased
65
Zn
2+
uptake and growth in minimal medium. CFT073Δ
znu
demonstrated an intermediate decrease of
65
Zn
2+
uptake and growth in minimal medium, whereas the CFT073Δ
zupT
mutant grew as well as CFT073 and exhibited a less marked decrease in
65
Zn
2+
uptake. CFT073 mutants grew as well as the wild type in human urine. In competitive infections in CBA/J mice, the Δ
zupT
mutant demonstrated no disadvantage during urinary tract infection. In contrast, the UPEC Δ
znu
and Δ
znu
Δ
zupT
strains demonstrated significantly reduced numbers in the bladders (mean 4.4- and 30-fold reductions, respectively) and kidneys (mean 41- and 48-fold reductions, respectively). In addition, in single-strain infection experiments, the Δ
znu
and Δ
znu
Δ
zupT
mutants were reduced in the kidneys (
P
= 0.0012 and
P
< 0.0001, respectively). Complementation of the CFT073 Δ
znu
Δ
zupT
mutant with the
znuACB
genes restored growth in Zn-deficient medium and bacterial numbers in the bladder and kidneys. The loss of the zinc transport systems decreased both motility and resistance to hydrogen peroxide, which could be restored by supplementation with zinc. Overall, the results indicate that Znu and ZupT are required for growth in zinc limited-conditions, that Znu is the predominant zinc transporter, and that the loss of Znu and ZupT has a cumulative effect on fitness during UTI, which may in part be due to reduced resistance to oxidative stress and motility.
Salmonella
-Containing Vacuoles Display Centrifugal Movement Associated with Cell-to-Cell Transfer in Epithelial Cells
Authors: Szeto Jason , Namolovan Anton , Osborne Suzanne E. , Coombes Brian K. , Brumell John H. 
Published: December 2008

ABSTRACT

Intracellular
Salmonella enterica
serovar Typhimurium (serovar Typhimurium) occupies a
Salmonella
-containing vacuole (SCV) where bacterial effector proteins are secreted into the host cell using type III secretion systems (T3SS). Cytoskeletal motor proteins and T3SS-delivered effector proteins facilitate SCV positioning to juxtanuclear positions where bacterial replication occurs. Here, we show that this characteristic SCV positioning is not maintained by all SCVs during infection of HeLa cells. Notably, juxtanuclear SCV localization that occurs by 8 to 14 h postinfection is followed by significant centrifugal displacement of a subset of SCVs toward the host cell periphery by 24 h postinfection. This novel phenotype requires bacterial protein synthesis, a functional
Salmonella
pathogenicity island 2 (SPI-2)-encoded T3SS, intact microtubules, and kinesin-1 motor protein. Bacteria lacking PipB2, a kinesin-recruiting T3SS effector, did not exhibit centrifugal displacement and remained at juxtanuclear positions throughout 24 h of infection. While levels of the SPI-2 effectors PipB2 and SifA increased during 24 h postinfection, a corresponding decrease in levels of the SPI-1 T3SS effectors SipA and SopB, both known to mediate juxtanuclear SCV positioning, was observed. A fluorescence-based assay indicated that wild-type serovar Typhimurium transferred from infected to uninfected epithelial cells while strains deficient in SPI-2 T3SS secretion or PipB2 did not. Our results reveal a novel SCV phenotype implicated in the cell-to-cell spread of serovar Typhimurium during infection.
Major Surface Protein LipL32 Is Not Required for Either Acute or Chronic Infection with
Leptospira interrogans
Authors: Murray Gerald L. , Srikram Amporn , Hoke David E. , Wunder Elsio A. , Henry Rebekah , Lo Miranda , Zhang Kunkun , Sermswan Rasana W. , Ko Albert I. , Adler Ben 
Published: December 2008

ABSTRACT

Leptospira interrogans
is responsible for leptospirosis, a zoonosis of worldwide distribution. LipL32 is the major outer membrane protein of pathogenic leptospires, accounting for up to 75% of total outer membrane protein. In recent times LipL32 has become the focus of intense study because of its surface location, dominance in the host immune response, and conservation among pathogenic species. In this study, an
lipL32
mutant was constructed in
L. interrogans
using transposon mutagenesis. The
lipL32
mutant had normal morphology and growth rate compared to the wild type and was equally adherent to extracellular matrix. Protein composition of the cell membranes was found to be largely unaffected by the loss of LipL32, with no obvious compensatory increase in other proteins. Microarray studies found no obvious stress response or upregulation of genes that may compensate for the loss of LipL32 but did suggest an association between LipL32 and the synthesis of heme and vitamin B
12
. When hamsters were inoculated by systemic and mucosal routes, the mutant caused acute severe disease manifestations that were indistinguishable from wild-type
L. interrogans
infection. In the rat model of chronic infection, the LipL32 mutant colonized the renal tubules as efficiently as the wild-type strain. In conclusion, this study showed that LipL32 does not play a role in either the acute or chronic models of infection. Considering the abundance and conservation of LipL32 among all pathogenic
Leptospira
spp. and its absence in saprophytic
Leptospira
, this finding is remarkable. The role of this protein in leptospiral biology and pathogenesis thus remains elusive.
Characterization of the Cpx Regulon inEscherichia coliStrain MC4100
Authors: Price Nancy L. , Raivio Tracy L. 
Published: December 2008

ABSTRACTThe Cpx two-component signal transduction pathway ofEscherichia colimediates adaptation to envelope protein misfolding. However, there is experimental evidence that at least 50 genes in 34 operons are part of the Cpx regulon and many have functions that are undefined or unrelated to envelope protein maintenance. No comprehensive analysis of the Cpx regulon has been presented to date. In order to identify strongly Cpx-regulated genes that might play an important role(s) in envelope protein folding and/or to further define the role of the Cpx response and to gain insight into what makes a gene subject to strong Cpx regulation, we have carried out a uniform characterization of a Cpx-regulatedluxreporter library in a single-strain background. Strongly Cpx-regulated genes encode proteins that are directly linked to envelope protein folding, localized to the envelope but uncharacterized, or involved in limiting the cellular concentration of noxious molecules. Moderately Cpx-regulated gene clusters encode products implicated in biofilm formation. An analysis of CpxR binding sites in strongly regulated genes indicates that while neither a consensus match nor their orientation predicts the strength of Cpx regulation, most genes contain a CpxR binding site within 100 bp of the transcriptional start site. Strikingly, we found that while there appears to be little overlap between the Cpx and Bae envelope stress responses, the σEand Cpx responses reciprocally regulate a large group of strongly Cpx-regulated genes, most of which are uncharacterized.
The Membrane Lipoprotein LppX of
Paenibacillus
sp. Strain W-61 Serves as a Molecular Chaperone for Xylanase of Glycoside Hydrolase Family 11 during Secretion across the Cytoplasmic Membrane
Authors: Fukuda Mutsumi , Watanabe Seiji , Kaneko Jun , Itoh Yoshifumi , Kamio Yoshiyuki 
Published: December 2008

ABSTRACT

Paenibacillus
sp. strain W-61, which can utilize xylan as the sole source of carbon and energy, produces extracellular xylanases 1 and 3 (Xyn1 and Xyn3) and cell surface xylanase 5. In this study we found that
lppX
, immediately downstream of
xyn1
, encodes a lipoprotein located on the outer layer of the cytoplasmic membrane and that the LppX lipoprotein is essential for the secretion of active Xyn1 across the cytoplasmic membranes. In
Escherichia coli
, wild-type LppX was destined for the inner layer of the outer membrane. Mutant LppX(C19A), in which Cys-19, a possible lipomodification residue, is replaced with Ala, was located in the periplasm without being anchored to the membranes. Another mutant, LppX(S20D S21D), with substitutions of Asp for Ser-20 and Ser-21 (conversion to an Asp-Asp signal for sorting to the inner membrane), resided on the outer layer of the inner membrane, demonstrating that LppX has the sorting property of a lipoprotein.
E. coli
harboring both
xyn1
and
lppX
secreted active Xyn1 into the periplasm. In contrast,
E. coli
carrying
xyn1
alone failed to do so, accumulating inactive Xyn1 in the cytoplasmic membranes. Exogenous LppX(C19A) liberated the inactive Xyn1, which had been stagnating in the inner membrane, into the medium as an active enzyme. Thus, we propose that LppX is a novel type of lipoprotein that assists Xyn1 in making the proper fold necessary for traveling across the cytoplasmic membranes to be secreted as an active enzyme.
An Intercultural Dialogue between the Muslim Taifa of Denia and the Christian County of Barcelona in the Eleventh Century
Authors: Bruce Travis 
Published: December 2008

AbstractPoints of dialogue increased across the Muslim–Christian Iberian frontier over the course of the eleventh century. Rulers on both sides pursued policies of active communication, through violent and pacific means. This is especially evident in the relations between Denia and Barcelona. The growing Mediterranean interests of both polities brought them into frequent contact through trade, diplomacy and conflict. In fact, the intercultural entente established between the rulers of Denia and Barcelona allows for a much broader view of Iberian Muslim–Christian relations within the context of the eleventh-century Western Mediterranean.
Scent of a Mystic Woman: Teresa de Jesús and the Interior Castle
Authors: Carrión María 
Published: December 2008

AbstractIn 1577 Teresa de Jesús composed the Interior Castle, an account of her spiritual experiences that deployed architectural images designed to incite readers to piety and devotion. Critical readings have identified the castle as a spiritual and aesthetic emblem of Christian hegemony, emplotting de Jesús's works in the rhetorical frame of Reconquista narratives. But the Castle, like the houses in the 1562 Book of Life and the palaces in the 1562-1564 Way of Perfection, moves readers to remember landscapes that differ from a monocultural event, as it narrates the ultimate spiritual encounter in frank dissidence with the hegemonic politics and aesthetics of Catholicism that became the law of the land in Spain after 1492. In line with a diversity of medieval mystical traditions from Europe and the Middle East, the choice of a castle—a key architectural sign of the Middle Ages—as the place of paradox, memory, and experience of the sublime offers clues that de Jesús figured out a way to communicate what seemed to be an unaccountable event in Counter-Reformation Spain: being in the presence of divinity and living to tell such story in cross-confessional terms. This essay analyzes the polysemic traces of the castle built by this mystic woman with the figurative fragrance of multicultural medieval Iberia, a space where she carefully negotiated war, crusades, and other kingdoms of heaven with contemplation, survival (pervivencia), and adaptation.
Remote Ischemic Preconditioning Stimulus Does Not Reduce Microvascular Resistance or Improve Myocardial Blood Flow in Patients Undergoing Elective Percutaneous Coronary Intervention
Authors: Hoole Stephen P. , Heck Patrick M. , White Paul A. , Khan Sadia N. , O'Sullivan Michael , Clarke Sarah C. , Dutka David P. 
Published: December 2008

Introduction Remote ischemic preconditioning (RIPC) may limit myocardial infarction by improving microvascular function and maintaining myocardial blood flow. We hypothesized that a RIPC stimulus would reduce coronary microvascular resistance and improve coronary blood flow during elective percutaneous coronary intervention (PCI). Method We prospectively recruited 54 patients with multi-vessel disease (MVD = 32) or single vessel disease awaiting elective PCI. Patients with MVD had non-target vessel (NTV) index of micro-circulatory resistance (IMR) determined, before and after target vessel (TV) PCI (cardiac RIPC). The effect of arm RIPC on serial microvascular resistance (Rp) was assessed in patients with single vessel disease. Results TV balloon occlusion did not alter the NTV IMR: 16.5 (12.4) baseline vs. 17.6 (11.6) post cardiac RIPC, P = 0.65 or hyperaemic transit time. Arm RIPC did not alter Rp in patients with single vessel disease: Rp, mmHg.cm-1.s-1: 3.5 (1.9) baseline vs. 4.1 (3.0) post arm RIPC, P = 0.19 and coronary flow velocity remained constant. Conclusion RIPC stimuli during elective PCI do not affect coronary microvascular resistance or coronary flow in humans.
Social Coping Among Academically Gifted Adolescents in a Residential Setting: A Longitudinal Study
Authors: Cross Tracy L. , Swiatek Mary Ann 
Published: December 2008

Much of the research on the social coping of students with gifts and talents has relied on a single administration of an instrument while the participants were attending a summer program. This study attempts to understand how attendance at a residential high school (academy) may affect academically gifted students over time. Students in two graduating classes at the academy completed the Social Coping Questionnaire on two (class of 2006) or three (class of 2005) occasions during their 2 years at the academy. Significant differences across approximately the first year at the academy are found for the items denying giftedness (more common after a year at the academy), social interaction (less common after a year at the academy), and peer acceptance (higher after a year at the academy). Putting the Research to Use: Schools are inherently sccial enterprises. Research has demonstrated that students with gifts and talents often learn coping behaviors to navigate the social milieus of their schools. Because students have agency, they have the capability to modify their social coping strategies based on their perceptions and social goals. This paper sheds light on both the soical coping behaviors of 300 academically gifted students upon entering a residental school for gifted adolescents and how they adapted to the new community over a two-period. The results of this study allow the reader to understand the complexities of school environments as social contexts and how students with gifts and talents cope with them.
The Use of the Peabody Individual Achievement Test and the Woodcock Reading Mastery Tests in the Diagnosis of a Learning Disability in Reading: A Caveat
Authors: Caskey William E. 
Published: December 2008

The Peabody Individual Achievement Test (PIAT, Dunn & Markwardt, 1970) and the Woodcock Reading Mastery Tests (Woodcock, 1973) are two tests widely used for the purpose of: a) The diagnosis of learning disabilities. For example, in Tennessee there must be a discrepancy of more than one standard deviation between expected and actual reading level, while in Ohio the difference must be two standard deviations. b) The demonstration of gain scores to assess the efficacy of instructional strategies or teaching effectiveness.
The Problems of Definition and Differentiation and the Need for a Classification Schema
Authors: Adelman Howard S. , Taylor Linda , Adelman Howard , Taylor Linda 
Published: December 2008

From both a theoretical and practical perspective, the majority of respondents to the future survey recognized the as yet unmet need to develop valid procedures for differential diagnosis and subtyping of learning disabilities. The foundation for developing such procedures was seen as requiring agreement about the definition of LD and appropriate ways to operationalize the definition. There was, however, a major split among the respondents regarding how LD should be defined. Some wanted to keep the definition tied to learning problems stemming from central nervous system dysfunctions; others wanted to ignore cause and broaden the field by defining as LD any learning problem that is not readily understood. These contrasting views about definition were then reflected in the controversy among respondents about operational criteria, e.g., the appropriateness and feasibility of identifying LD based on a severe discrepancy between aptitude and achievement. Another concern was raised in connection with the matter of identifying LD subtypes, i.e., some respondents viewed such efforts as confounded by the lack of satisfactory procedures for differentiating LD from learning problems caused by other factors. In general, then, the survey responses underscore the controversy and widespread frustration over definition and differentiation and suggest that the LD field's future integrity is very much dependent on successfully dealing with these problems. It is time, we think, for the field to take a step back from narrow debates over definition and deal with the fundamental problem of developing a comprehensive classification scheme, i.e., one in which LD is differentiated from other categories of learning problems and subtypes are conceived within each category. The following paper on definition and subtypes focuses briefly on the nature of the definition and differentiation problems, the importance of placing and keeping LD in perspective vis à vis other learning problems, and ideas related to future development of a LD classification schema. (We should note that, in the course of recent events, the preparation of this paper for the series fell to us.)
A Comparison of Differences Between Students Labeled Learning Disabled and Low Achieving on Measures of Classroom Performance
Authors: Shinn Mark R. , Ysseldyke James E. , Deno Stanley L. , Tindal Gerald A. 
Published: December 2008

Editor's Comments: Much has been written about the identification of the learning disabled. The two following articles found that identified learning disabled populations are indeed different from other types of school populations on specific variables. However, the authors differ on some critical points. Readers' comments are welcome.—JLW Classroom performance measures of reading, spelling, and written expression developed at the University of Minnesota Institute for Research on Learning Disabilities were administered weekly over a 5-week period to 71 fifth-grade students. Although 34 of these students had been identified as LD by their schools and 37 were low achievers who had not been identified as LD, no meaningful differences had been found between their performances on several commonly used norm-referenced devices. Examination of the students' weekly performance on the classroom performance measures revealed both significant and practical differences in performance on the measures of reading, spelling, and spelling accuracy on a written expression task; no differences were found in their rates of improvement over the 5-week period. Students did not differ significantly in other methods of evaluating their writing. In general, the findings support the hypothesis that teachers' referral decisions are based on what they observe students doing in the classroom and that the subsequent administration of norm-referenced tests may reflect an inefficient confirmatory process. The implications of the findings for classification of students as LD and current practice are discussed.
Lead Levels and Child Development
Authors: Ernhart Claire B. , Needleman Herbert L. 
Published: December 2008

In the December 1974 issue of this journal, J. Perino and C.B. Ernhart reported that moderate levels of lead exposure in 80 preschool, urban, black children were related to cognitive impairment. In October of 1985, C.B. Ernhart, B. Landa, and A.W. Wolf pre-sented a re-analysis of the data reported in the 1974 article. These researchers revised the position originally taken by Perino and Ernhart and concluded, based on their re-analysis, that if there was an effect of lead levels on cognitive development, it was minimal. In the June/July 1986 issue of this journal, H.L. Needleman presented an argument against the methodology used in the re-analysis of the data by C.B. Ernhart and her colleagues. He felt that it was inappropriate to conclude, based on such a data analysis, that the relationship of lead level and cognitive development was of little consequence in the sample of children. C.B. Ernhart, in a response to his argument in the June/July 1986 issue, continued to support the re-analysis and findings. Correspondence regarding the data analysis has continued, and I asked five mem-bers of the JLD Board of Consulting Editors to review the articles, data, and correspon-dence on this matter. After careful study, we all agreed that because of the importance of the topic, space should again be devoted to it. In the following Commentary, Ernhart and Needleman present statements on their respective positions; I will conclude with a brief editorial statement.—JLW
The Effectiveness of Graphic Organizers for Three Classifications of Secondary Students in Content Area Classes
Authors: Horton Steven V. , Lovitt Thomas C. , Bergerud Donna 
Published: December 2008

The purpose of the Interventions section of the journal is to provide professional practitioners with overviews of successful interventions that can be replicated with individuals with learning disabilities. These interventions can be either physiological or psychoeducational and can occur in school settings, clinics, hospitals, homes, communities, or employment sites. The discussion of these interventions generally includes (a) the theory or rationale of the interventions, (b) previous research findings, (c) characteristics of the individuals receiving the interventions, (d) the intervention that was applied, and (e) the criteria used to evaluate its success. In the first article, Steven V. Horton, Thomas C. Lovitt, and Donna Bergerud of the University of Washington describe the effectiveness of graphic organizers. In the second article, Bernadette Kelly, Russell Gersten, and Douglas Carnine of the University of Oregon describe the importance of curriculum design in teaching fractions. It would appear that careful attention to the use of graphic organizers and a well-designed curriculum can be beneficial in helping students with learning disabilities learn in content area classes and in mathematics, respectively.—JLW Previous research concerning the graphic or visual display of information with academically handicapped students has not addressed the instructional conditions that exist in mainstream settings. This article investigates the effectiveness of graphic organizers for three classifications of secondary students enrolled in content area classes: students with learning disabilities, remedial students, and students in regular education. The results of three separate experiments indicated that graphic organizers, whether teacher-directed, student-directed with text references, or student-directed with clues, produced significantly higher performance than self-study for each group of students. Several practical issues involving the use of graphic organizers with heterogeneous groups of secondary students are discussed.