bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extent of Horizontal Gene Transfer in Evolution of Streptococci of the Salivarius Group
Authors: Delorme Christine , Poyart Claire , Ehrlich S. Dusko , Renault Pierre 
Published: February 2007

ABSTRACT

The phylogenetically closely related species
Streptococcus salivarius
and
Streptococcus vestibularis
are oral bacteria that are considered commensals, although they can also be found in human infections. The relationship between these two species and the relationship between strains isolated from carriers and strains responsible for invasive infections were investigated by multilocus sequence typing and additional sequence analysis. The clustering of several
S. vestibularis
alleles and the extent of genomic divergence at certain loci support the conclusion that
S. salivarius
and
S. vestibularis
are separate species. The level of sequence diversity in
S. salivarius
alleles is generally high, whereas that in
S. vestibularis
alleles is low at certain loci, indicating that the latter species might have evolved recently. Cluster analysis indicated that there has been genetic exchange between
S. salivarius
and
S. vestibularis
at three of the nine loci investigated. Horizontal gene transfer between streptococci belonging to the
S. salivarius
group and other oral streptococci was also detected at several loci. A high level of recombination in
S. salivarius
was revealed by allele index association and split decomposition sequence analyses. Commensal and infection-associated
S. salivarius
strains could not be distinguished by cluster analysis, suggesting that the pathogen isolates are opportunistic. Taken together, our results indicate that there is a high level of gene exchange that contributes to the evolution of two streptococcal species from the human oral cavity.
TheyefM-yoeBToxin-Antitoxin Systems ofEscherichia coliandStreptococcus pneumoniae: Functional and Structural Correlation
Authors: Nieto Concha , Cherny Izhack , Khoo Seok Kooi , de Lacoba Mario García , Chan Wai Ting , Yeo Chew Chieng , Gazit Ehud , Espinosa Manuel 
Published: February 2007

ABSTRACTToxin-antitoxin loci belonging to theyefM-yoeBfamily are located in the chromosome or in some plasmids of several bacteria. We cloned theyefM-yoeBlocus ofStreptococcus pneumoniae, and these genes encode bona fide antitoxin (YefMSpn) and toxin (YoeBSpn) products. We showed that overproduction of YoeBSpnis toxic toEscherichia colicells, leading to severe inhibition of cell growth and to a reduction in cell viability; this toxicity was more pronounced in anE. coliB strain than in twoE. coliK-12 strains. The YoeBSpn-mediated toxicity could be reversed by the cognate antitoxin, YefMSpn, but not by overproduction of theE. coliYefM antitoxin. The pneumococcal proteins were purified and were shown to interact with each other both in vitro and in vivo. Far-UV circular dichroism analyses indicated that the pneumococcal antitoxin was partially, but not totally, unfolded and was different than itsE. colicounterpart. Molecular modeling showed that the toxins belonging to the family were homologous, whereas the antitoxins appeared to be specifically designed for each bacterial locus; thus, the toxin-antitoxin interactions were adapted to the different bacterial environmental conditions. Both structural features, folding and the molecular modeled structure, could explain the lack of cross-complementation between the pneumococcal andE. coliantitoxins.
Group B Streptococcal Capsular Sialic Acids Interact with Siglecs (Immunoglobulin-Like Lectins) on Human Leukocytes
Authors: Carlin Aaron F. , Lewis Amanda L. , Varki Ajit , Nizet Victor 
Published: February 2007

ABSTRACT

Group B
Streptococcus
(GBS) is classified into nine serotypes that vary in capsular polysaccharide (CPS) architecture but share in common the presence of a terminal sialic acid (Sia) residue. This position and linkage of GBS Sia closely resembles that of cell surface glycans found abundantly on human cells. CD33-related Siglecs (CD33rSiglecs) are a family of Sia-binding lectins expressed on host leukocytes that engage host Sia-capped glycans and send signals that dampen inflammatory gene activation. We hypothesized that GBS evolved to display CPS Sia as a form of molecular mimicry limiting the activation of an effective innate immune response. In this study, we applied a panel of immunologic and cell-based assays to demonstrate that GBS of several serotypes interacts in a Sia- and serotype-specific manner with certain human CD33rSiglecs, including hSiglec-9 and hSiglec-5 expressed on neutrophils and monocytes. Modification of GBS CPS Sia by O acetylation has recently been recognized, and we further show that the degree of O acetylation can markedly affect the interaction between GBS and hSiglec-5, -7, and -9. Thus, production of Sia-capped bacterial polysaccharide capsules that mimic human cell surface glycans in order to engage CD33rSiglecs may be an example of a previously unrecognized bacterial mechanism of leukocyte manipulation.
Real-Time PCR Assay for Detection of Quinolone-Resistant
Neisseria gonorrhoeae
in Urine Samples
Authors: Siedner Mark J. , Pandori Mark , Castro Lina , Barry Pennan , Whittington William L. H. , Liska Sally , Klausner Jeffrey D. 
Published: February 2007

ABSTRACT

A need exists for the development of applicable surveillance tools to detect fluoroquinolone-resistant
Neisseria gonorrhoeae
(QRNG) in urine samples. We describe here a real-time PCR assay for detecting mutations in the Ser91 codon of the
gyrA
gene of
N. gonorrhoeae
in urine specimens. We tested 96 urine samples collected along with Gonorrhea Isolate Surveillance Project (GISP) urethral swab samples and compared the results with matched MICs of ciprofloxacin, as reported by the regional GISP laboratory. We then tested 100 urine specimens, known to be gonorrhea positive by nucleic acid amplification testing, provided by females to challenge the real-time PCR assay with urine specimens containing potentially less target DNA content than specimens from symptomatic males. With an MIC threshold of 0.125 μg of ciprofloxacin/ml, our assay correctly identified resistance in 41 of 44 (93.2%; 95% confidence interval [CI] = 81.3 to 98.6%) corresponding resistant culture specimens and correctly identified 51 of 51 (100%; 95% CI = 93.0 to 100%) susceptible specimens. One specimen did not amplify. The assay successfully amplified the
gyrA
amplicon and determined a susceptibility genotype in 72 of 100 (72%) urine specimens collected from female patients. We developed an assay for detecting QRNG in urine specimens that correlated well with MIC results of cultured specimens and had moderate sensitivity with urine specimens. This methodology might fulfill the need for a QRNG detection system for urine specimens, a useful characteristic in the age of nucleic acid amplification testing for gonococcal infection.
Survival of Fastidious and Nonfastidious Aerobic Bacteria in Three Bacterial Transport Swab Systems
Authors: Rishmawi Nabeel , Ghneim Raed , Kattan Randa , Ghneim Riyad , Zoughbi Madeleine , Abu-Diab Afaf , Turkuman Sultan , Dauodi Rula , Shomali Issa , Issa Abed El-Razeq , Siriani Issa , Marzouka Hiyam , Schmid Irmgard , Hindiyeh Musa Y. 
Published: February 2007

ABSTRACT

In the present study, we followed the CLSI procedure M40-A to evaluate three specimen transport systems [the new BD CultureSwab MaxV(+), the new Remel BactiSwab, and the Medical Wire & Equipment Transwab] for the survival of fastidious and nonfastidious organisms for 0, 6, 24, and 48 h at room temperature. BD CultureSwab MaxV(+) outperformed the other two swabs for the recovery of the three fastidious organisms,
Haemophilus influenzae
,
Neisseria gonorrhoeae
, and
Neisseria meningitidis
for up to 48 h. Indeed, BD CultureSwab MaxV(+) maintained a constant number of viable
H. influenzae
and
N. meningitidis
for up to 48 h, and only a 2 log reduction was noted for
N. gonorrhoeae
, fulfilling the requirements of M40-A guidelines. However, unlike Remel BactiSwab and the Medical Wire & Equipment Transwab, which fulfilled the M40-A requirements for maintaining the viability of
Streptococcus pneumoniae
, BD CultureSwab MaxV(+) could not maintain the viability of
S. pneumoniae
reference or clinical strains past 6 h. Excellent overall sensitivity (98%) (95% confidence interval, 89.5 to 99.7) was observed when the BD CultureSwab MaxV(+) rectal swabs were compared to the “gold standard” stool cultures. Thus, the BD CultureSwab MaxV(+) rectal swab can be used when investigating gastrointestinal bacterial outbreaks or when health care providers face difficulties in obtaining stool samples, particularly from children.
Rotavirus Infection Alters Peripheral T-Cell Homeostasis in Children with Acute Diarrhea
Authors: Wang Yuhuan , Dennehy Penelope H. , Keyserling Harry L. , Tang Kevin , Gentsch Jon R. , Glass Roger I. , Jiang Baoming 
Published: February 2007

ABSTRACT
The patterns of gene expression and the phenotypes of lymphocytes in peripheral blood mononuclear cells (PBMC) from children with diarrhea caused by rotavirus and healthy children were compared by using DNA microarray, quantitative PCR, and flow cytometry. We observed increased expression of a number of genes encoding proinflammatory cytokines and interferon or interferon-stimulated proteins and demonstrated activation of some genes involved in the differentiation, maturation, activation, and survival of B lymphocytes in PBMC of patients with rotavirus infection. In contrast, we observed a consistent pattern of lower mRNA levels for an array of genes involved in the various stages of T-cell development and demonstrated a reduction in total lymphocyte populations and in the proportions of CD4 and CD8 T lymphocytes from PBMC of patients. This decreased frequency of T lymphocytes was transient, since the proportions of T lymphocytes recovered to almost normal levels in convalescent-phase PBMC from most patients. Finally, rotavirus infection induced the activation and expression of the early activation markers CD83 and CD69 on a fraction of CD19 B cells and the remaining CD4 and CD8 T lymphocytes in acute-phase PBMC of patients; the expression of CD83 continued to be elevated and was predominantly exhibited on CD4 T lymphocytes in convalescent-phase PBMC. On the basis of these findings at the molecular, phenotypic, and physiologic levels in acute-phase PBMC, we conclude that rotavirus infection induces robust proinflammatory and antiviral responses and B-cell activation but alters peripheral T-cell homeostasis in children.
NFX1-123 and Poly(A) Binding Proteins Synergistically Augment Activation of Telomerase in Human Papillomavirus Type 16 E6-Expressing Cells
Authors: Katzenellenbogen Rachel A. , Egelkrout Erin M. , Vliet-Gregg Portia , Gewin Lindy C. , Gafken Philip R. , Galloway Denise A. 
Published: February 2007

ABSTRACT

Overcoming senescence signals in somatic cells is critical to cellular immortalization and carcinogenesis. High-risk human papillomavirus (HPV) can immortalize epithelial cells in culture through degradation of the retinoblastoma protein by HPV E7 and activation of
hTERT
transcription, the catalytic subunit of telomerase, by the heterodimer HPV E6/E6-associated protein (E6AP). Recent work in our laboratory identified a novel repressor of
hTERT
transcription, NFX1-91, which is targeted for ubiquitin-mediated degradation by HPV type 16 (HPV16) E6/E6AP. In contrast, NFX1-123, a splice variant NFX1, increased expression from an
hTERT
promoter that was activated by HPV16 E6/E6AP. Here, we show that HPV16 E6 bound both NFX1-91 and NFX1-123 through the common central domain of NFX1 in the absence of E6AP. NFX1-123 positively regulated hTERT expression, as its knockdown decreased hTERT mRNA levels and telomerase activity and its overexpression increased telomerase activity. We identified new protein partners of NFX1-123, including several cytoplasmic poly(A) binding proteins (PABPCs) that interacted with NFX1-123 through its N-terminal PAM2 motif, a protein domain characteristic of other PABPC protein partners. Furthermore, NFX1-123 and PABPCs together had a synergistic stimulatory effect on
hTERT
-regulated reporter assays. The data suggest that NFX1-123 is integral to hTERT regulation in HPV16 E6-expressing epithelial cells and that the interaction between NFX1-123 and PABPCs is critical to hTERT activity.
The Nanovirus-Encoded Clink Protein Affects Plant Cell Cycle Regulation through Interaction with the Retinoblastoma-Related Protein
Authors: Lageix Sébastien , Catrice Olivier , Deragon Jean-Marc , Gronenborn Bruno , Pélissier Thierry , Ramírez Bertha Cecilia 
Published: February 2007

ABSTRACT

Nanoviruses, multicomponent single-stranded DNA plant viruses, encode a unique cell cycle link protein, Clink, that interacts with retinoblastoma-related proteins (RBR). We have established transgenic
Arabidopsis thaliana
lines that conditionally express Clink or a Clink variant deficient in RBR binding. By controlled induction of Clink expression, we demonstrated the capacity of the Clink protein to alter RBR function in vivo. We showed that transcription of both S-phase-specific and G
2
/M-phase-specific genes was up-regulated depending on the RBR-binding proficiency of Clink. Concomitantly, ploidy levels increased in a substantial fraction of leaf cell nuclei. Also, leaf epidermis cells of transgenic plants producing Clink were smaller and more numerous, indicating additional cell divisions in this tissue. Furthermore, cytogenetic analyses following induction of Clink expression in mature leaves revealed the presence of metaphasic and anaphasic nuclei, clear evidence that Clink-mediated RBR inactivation is sufficient to induce quiescent cells to reenter cell cycle progression and, for at least a fraction of them, to pass through mitosis. Expression of Clink had no effect on genes transcribed by RNA polymerases I and III, suggesting that, in contrast to its mammalian homologue,
A. thaliana
RBR is not involved in the repression of polymerase I and polymerase III transcription. The results of these in vivo analyses firmly establish Clink as a member of the diverse class of multifunctional cell cycle modulator proteins encoded by small DNA viruses.
Bitopic Membrane Topology of the Stable Signal Peptide in the Tripartite Junín Virus GP-C Envelope Glycoprotein Complex
Authors: Agnihothram Sudhakar S. , York Joanne , Trahey Meg , Nunberg Jack H. 
Published: February 2007

ABSTRACT
The stable signal peptide (SSP) of the GP-C envelope glycoprotein of the Junín arenavirus plays a critical role in trafficking of the GP-C complex to the cell surface and in its membrane fusion activity. SSP therefore may function on both sides of the lipid membrane. In this study, we have investigated the membrane topology of SSP by confocal microscopy of cells treated with the detergent digitonin to selectively permeabilize the plasma membrane. By using an affinity tag to mark the termini of SSP in the properly assembled GP-C complex, we find that both the N and C termini reside in the cytosol. Thus, SSP adopts a bitopic topology in which the C terminus is translocated from the lumen of the endoplasmic reticulum to the cytoplasm. This model is supported by (i) the presence of two conserved hydrophobic regions in SSP (hφ1 and hφ2) and (ii) our previous demonstration that lysine-33 in the ectodomain loop is essential for pH-dependent membrane fusion. Moreover, we demonstrate that the introduction of a charged side chain or single amino acid deletion in the membrane-spanning hφ2 region significantly diminishes SSP association in the GP-C complex and abolishes membrane fusion activity. Taken together, our results suggest that bitopic membrane insertion of SSP is centrally important in the assembly and function of the tripartite GP-C complex.
DR WHO: a workshop for house officer preparation
Authors: Cave Judith , Wallace Deirdre , Baillie Glenda , Klingenberg Michael , Phillips Catherine , Oliver Harriet , Rowles Katherine , Dunkley Lisa , Sturrock Alison , Dacre Jane 
Published: February 2007

Abstract

Background
Newly qualified doctors should be competent in advanced life support (ALS) and critical care. The Resuscitation Council has published a course about ALS for undergraduate medical students (the intermediate life support (ILS) course). However, there is no undergraduate-level course on assessing and treating critically ill patients, despite the fact that postgraduate courses on this topic are extremely popular. We have developed a new course called Direct Response Workshop for House Officer Preparation (DR WHO), which teaches both ALS and critical care at an undergraduate level.

Methods
We taught the Resuscitation Council ILS course to our 2003–4 cohort of final year medical students (n = 350), and the new course (DR WHO) to our 2004–5 cohort (n = 338). Students filled in feedback forms immediately after the courses, and a subset repeated the feedback forms 4 months after they had started work as house officers.

Course evaluation
Student and house officer feedback was positive. The DR WHO cohort was more confident in caring for critically ill patients (18/26 (69%) were confident after ILS, and 40/45 (89%) were confident after DR WHO (χ2 = 4.3; df = 1; p = 0.06)). Both cohorts were competent in ALS, each with a mean score of 18.6/20 in a finals level practical examination on this topic.

Conclusions
The DR WHO course is popular with the students and practical to run. The course needs to be re-evaluated to determine the long-term competency of graduates.
Endovascular abdominal aortic aneurysm repair
Authors: Norwood M G A , Lloyd G M , Bown M J , Fishwick G , London N J , Sayers R D 
Published: February 2007

Abstract
The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.
In vitro biological activity of a novel small-molecule inhibitor of polo-like kinase 1
Authors: Lansing Timothy J. , McConnell Randy T. , Duckett Derek R. , Spehar Glenn M. , Knick Victoria B. , Hassler Daniel F. , Noro Nobuhiro , Furuta Masaaki , Emmitte Kyle A. , Gilmer Tona M. , Mook Robert A. , Cheung Mui 
Published: February 2007

Abstract
Polo-like kinase 1 (PLK1) plays key roles in the regulation of mitotic progression, including mitotic entry, spindle formation, chromosome segregation, and cytokinesis. PLK1 expression and activity are strongly linked to proliferating cells. Many studies have shown that PLK1 expression is elevated in a variety of tumors, and high expression often correlates with poor prognosis. Using a variety of methods, including small-molecule inhibition of PLK1 function and/or activity, apoptosis in cancer cell lines, cell cycle arrest in normal cell lines, and antitumor activity in vivo have been observed. In the present study, we have examined the in vitro biological activity of a novel and selective thiophene benzimidazole ATP-competitive inhibitor of PLK1 and PLK3 (5-(5,6-dimethoxy-1H-benzimidazol-1-yl)-3-{[2-(trifluoromethyl)-benzyl]oxy}thiophene-2-carboxamide, called compound 1). Compound 1 has low nanomolar activity against the PLK1 and PLK3 enzymes and potently inhibits the proliferation of a wide variety of tumor cell lines. In the lung adenocarcinoma cell line NCI-H460, compound 1 induces a transient G2-M arrest, mitotic spindle defects, and a multinucleate phenotype resulting in apoptosis, whereas normal human diploid fibroblasts arrest in G2-M and show little apoptosis. We also describe a cellular mechanistic assay that was developed to identify potent intracellular inhibitors of PLK1. In addition to its potential as a therapeutic agent for treating cancer, compound 1 is also a useful tool molecule for further investigation of the biological functions of PLK1 and PLK3. [Mol Cancer Ther 2007;6(2):450–9]
High Frequency of a Retinoid X Receptor γ Gene Variant in Familial Combined Hyperlipidemia That Associates With Atherogenic Dyslipidemia
Authors: Nohara Atsushi , Kawashiri Masa-aki , Claudel Thierry , Mizuno Mihoko , Tsuchida Masayuki , Takata Mutsuko , Katsuda Shoji , Miwa Kenji , Inazu Akihiro , Kuipers Folkert , Kobayashi Junji , Koizumi Junji , Yamagishi Masakazu , Mabuchi Hiroshi 
Published: February 2007

Objective—The genetic background of familial combined hyperlipidemia (FCHL) has not been fully clarified. Because several nuclear receptors play pivotal roles in lipid metabolism, we tested the hypothesis that genetic variants of nuclear receptors contribute to FCHL.Methods and Results—We screened all the coding regions of the PPARα, PPARγ2, PPARδ, FXR, LXRα, and RXRγ genes in 180 hyperlipidemic patients including 60 FCHL probands. Clinical characteristics of the identified variants were evaluated in other 175 patients suspected of coronary disease. We identified PPARα Asp140Asn and Gly395Glu, PPARγ2 Pro12Ala, RXRγ Gly14Ser, and FXR −1g−>t variants. Only RXRγ Ser14 was more frequent in FCHL (15%,P<0.05) than in other primary hyperlipidemia (4%) and in controls (5%). Among patients suspected of coronary disease, we identified 9 RXRγ Ser14 carriers, who showed increased triglycerides (1.62±0.82 versus 1.91±0.42 [mean±SD] mmol/L,P<0.05), decreased HDL-cholesterol (1.32±0.41 versus 1.04±0.26,P<0.05), and decreased post-heparin plasma lipoprotein lipase protein levels (222±85 versus 149±38 ng/mL,P<0.01). In vitro, RXRγ Ser14 showed significantly stronger repression of the lipoprotein lipase promoter than RXRγ Gly14.Conclusion—These findings suggest that RXRγ contributes to the genetic background of FCHL.
Three-Dimensional Ageostrophic Motion in Mesoscale Vortex Dipoles
Authors: Pallàs-Sanz Enric , Viúdez Álvaro 
Published: February 2007

Abstract
The three-dimensional motion of mesoscale baroclinic dipoles is simulated using a nonhydrostatic Boussinesq numerical model. The initial conditions are two ellipsoidal vortices of positive and negative potential vorticity anomalies. The flow is moderately ageostrophic with a maximum absolute Rossby number equal to 0.71. The trajectory of the dipole is related to the maximum potential vorticity anomaly and size of the vortices. Three cases are considered depending on the curvature of the dipole trajectory: negative, close to zero, and positive. The ageostrophic flow strongly depends on the distance between the ellipsoidal vortices d0. For small d0 the vortices move steadily as a compact dipole, and the vertical velocity w has an octupolar three-dimensional pattern. The horizontal ageostrophic velocity is due to the advective acceleration of the flow, particularly the centripetal acceleration. The speed acceleration is only relatively important at the rear and front parts of the dipole axis, where the flow curvature is small but where the flow confluence and diffluence are, respectively, large. The geostrophy is maximal at the dipole center, on the dipole axis, where both curvature and speed acceleration are minimal. As d0 increases, the dipole self-propagating velocity and the extreme values of |w| decrease, and vortex oscillations highly distort the octupolar pattern of w. In all cases, as is typical of balanced mesoscale geophysical flows, the vertical velocity is related to the advection of vertical vorticity by the horizontal shear velocity uhz · ∇hζ.