bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mutational Analysis of Flucytosine Resistance in
Candida glabrata
Authors: Edlind Thomas D. , Katiyar Santosh K. 
Published: September 2010

ABSTRACT

The antifungal flucytosine (5-fluorocytosine [5FC]) is a prodrug metabolized to its toxic form, 5-fluorouracil (5FU), only by organisms expressing cytosine deaminase. One such organism is
Candida glabrata
, which has emerged as the second most common agent of bloodstream and mucosal candidiasis. This emergence has been attributed to the high rate at which
C. glabrata
develops resistance to azole antifungals. As an oral agent, 5FC represents an attractive alternative or complement to azoles; however, the frequency of 5FC resistance mutations and the mechanisms by which these mutations confer resistance have been explored only minimally. On RPMI 1640 medium containing 1 μg/ml 5FC (32-fold above the MIC, but less than 1/10 of typical serum levels), resistant mutants occurred at a relatively low frequency (2 × 10
−7
). Three of six mutants characterized were 5FU cross-resistant, suggesting a mutation downstream of the Fcy1 gene (cytosine deaminase), which was confirmed by sequence analysis of the Fur1 gene (uracil phosphoribosyl transferase). The remaining three mutants had Fcy1 mutations. To ascertain the effects of 5FC resistance mutations on enzyme function, mutants were isolated in
ura3
strains. Three of seven mutants harbored Fcy1 mutations and failed to grow in uridine-free, cytosine-supplemented medium, consistent with inactive Fcy1. The remainder grew in this medium and had wild-type Fcy1; further analysis revealed these to be mutated in the Fcy2L homolog of
S. cerevisiae
Fcy2 (purine-cytosine transporter). Based on this analysis, we characterized three 5FC-resistant clinical isolates, and mutations were identified in Fur1 and Fcy1. These data provide a framework for understanding 5FC resistance in
C. glabrata
and potentially in other fungal pathogens.
Pharmacokinetics-Pharmacodynamics of a Respiratory Syncytial Virus Fusion Inhibitor in the Cotton Rat Model
Authors: Rouan Marie-Claude , Gevers Tom , Roymans Dirk , de Zwart Loeckie , Nauwelaers David , De Meulder Marc , van Remoortere Pieter , Vanstockem Marc , Koul Anil , Simmen Kenny , Andries Koen 
Published: September 2010

ABSTRACTHuman respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in infants, young children, elderly persons, and severely immunocompromised patients. Effective postinfection treatments are not widely available, and currently there is no approved vaccine. TMC353121 is a potent RSV fusion inhibitorinvitro, and its ability to reduce viral loadsinvivowas demonstrated in cotton rats following prophylactic intravenous administration. Here, the pharmacokinetics of TMC353121 in the cotton rat, which is semipermissive for RSV replication, were further explored to build a pharmacokinetic-pharmacodynamic (PK-PD) model and to estimate the plasma drug levels needed for significant antiviral efficacy. TMC353121 reduced the viral titers in bronchoalveolar lavage fluid in a dose-dependent manner after a single subcutaneous administration and intranasal RSV inoculation 24 h after compound administration. The viral titer reduction and plasma TMC353121 concentration at the time of RSV inoculation were well described using a simpleEmaxmodel with a maximal viral titer reduction (Emax) of 1.5 log10. The plasma drug level required to achieve 50% of theEmax(200 ng/ml) was much higher than the 50% inhibitory concentration observedinvitroin HeLaM cells (0.07 ng/ml). In conclusion, this simple PK-PD approach may be useful in predicting efficacious exposure levels for future RSV inhibitors.
OI-57, a Genomic Island of
Escherichia coli
O157, Is Present in Other Seropathotypes of Shiga Toxin-Producing
E. coli
Associated with Severe Human Disease
Authors: Imamovic Lejla , Tozzoli Rosangela , Michelacci Valeria , Minelli Fabio , Marziano Maria Luisa , Caprioli Alfredo , Morabito Stefano 
Published: September 2010

ABSTRACT

Strains of Shiga toxin-producing
Escherichia coli
(STEC) are a heterogeneous
E. coli
group that may cause severe disease in humans. STEC have been categorized into seropathotypes (SPTs) based on their phenotypic and molecular characteristics and the clinical features of the associated diseases. SPTs range from A to E, according to a decreasing rank of pathogenicity. To define the virulence gene asset (“virulome”) characterizing the highly pathogenic SPTs, we used microarray hybridization to compare the whole genomes of STEC belonging to SPTs B, C, and D with that of STEC O157 (SPT A). The presence of the open reading frames (ORFs) associated with SPTs A and B was subsequently investigated by PCR in a larger panel of STEC and in other
E. coli
strains. A genomic island termed OI-57 was present in SPTs A and B but not in the other SPTs. OI-57 harbors the putative virulence gene
adfO
, encoding a factor enhancing the adhesivity of STEC O157, and
ckf
, encoding a putative killing factor for the bacterial cell. PCR analyses showed that OI-57 was present in its entirety in the majority of the STEC genomes examined, indicating that it represents a stable acquisition of the positive clonal lineages. OI-57 was also present in a high proportion of the human enteropathogenic
E. coli
genomes assayed, suggesting that it could be involved in the attaching-and-effacing colonization of the intestinal mucosa. In conclusion, OI-57 appears to be part of the virulome of pathogenic STEC and further studies are needed to elucidate its role in the pathogenesis of STEC infections.
Fusobacterium nucleatumOuter Membrane Proteins Fap2 and RadD Induce Cell Death in Human Lymphocytes
Authors: Kaplan Christopher W. , Ma Xiaoyuan , Paranjpe Avina , Jewett Anahid , Lux Renate , Kinder-Haake Susan , Shi Wenyuan 
Published: September 2010

ABSTRACTBacterially induced cell death in human lymphocytes is an important virulence factor for pathogenic bacteria. Previously discovered mechanisms of bacterially induced cell death are predominantly based on the transfer of bacterial proteins to the target host cell, such as the toxins secreted through type I, II, and VI secretion systems or effector proteins injected through type III, IV, and Vb secretion systems. Here, we report a mechanism employed by the Gram-negative oral pathogenFusobacterium nucleatumfor cell death induction of human lymphocytes via two outer membrane proteins (OMPs), Fap2 and RadD, which share regions homologous to autotransporter secretion systems (type Va secretion systems). Genetic and physiological studies established that inactivation of the two OMPs led to significantly reduced ability to trigger cell death in Jurkat cells, while the corresponding double mutant was almost completely attenuated. Additional biochemical and molecular analyses demonstrated that cell-freeF. nucleatummembranes are sufficient to induce cell death in Jurkat cells, suggesting that no active process or effector protein transfer was necessary to induce eukaryotic cell death.
Hierarchical, Domain Type-Specific Acquisition of Antibodies to
Plasmodium falciparum
Erythrocyte Membrane Protein 1 in Tanzanian Children
Authors: Cham Gerald K. K. , Turner Louise , Kurtis Jonathan D. , Mutabingwa Theonest , Fried Michal , Jensen Anja T. R. , Lavstsen Thomas , Hviid Lars , Duffy Patrick E. , Theander Thor G. 
Published: September 2010

ABSTRACT

Plasmodium falciparum
erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of malaria-infected erythrocytes. PfEMP1 attaches to the vascular lining and allows infected erythrocytes to avoid filtration through the spleen. Each parasite genome encodes about 60 different PfEMP1 variants, each PfEMP1 comprises several domains in its extracellular region, and the PfEMP1 repertoire in different parasites contains domain types that are serologically cross-reactive. In this longitudinal study, we followed 672 children living in an area of high malaria transmission during the first years of life and compared the acquisitions of antibodies to 32 Duffy-binding ligand-like (DBL) domains representing different types. For each child, we determined whether an antibody response to each domain was acquired before, after, or at the same time as responses to each of the other domains. We next used this information to calculate population-level odds ratios to measure the odds that antibodies to a given domain were acquired before antibodies to other domains. Odds ratios for 269 of the 496 possible domain combinations were statistically significant. Thus, the sequence in which individuals acquire antibodies to different PfEMP1 domains is ordered, and children in areas of endemicity first acquire antibodies to particular PfEMP1 domains encoded by the so-called group A and B/A
var
genes. The results imply that anti-PfEMP1 antibodies effectively structure PfEMP1 expression and play a major role in limiting parasite multiplication in the blood.
Critical Role for the Host GTPase-Activating Protein ARAP2 in InlB-Mediated Entry of
Listeria monocytogenes
Authors: Gavicherla Balramakrishna , Ritchey Lisa , Gianfelice Antonella , Kolokoltsov Andrey A. , Davey Robert A. , Ireton Keith 
Published: September 2010

ABSTRACT

The bacterial pathogen
Listeria monocytogenes
causes food-borne illnesses culminating in gastroenteritis, meningitis, or abortion.
Listeria
induces its internalization into some mammalian cells through binding of the bacterial surface protein InlB to the host receptor tyrosine kinase Met. Interaction of InlB with the Met receptor elicits host downstream signaling pathways that promote F-actin cytoskeletal changes responsible for pathogen engulfment. Here we show that the mammalian signaling protein ARAP2 plays a critical role in cytoskeletal remodeling and internalization of
Listeria
. Depletion of ARAP2 through RNA interference (RNAi) caused a marked inhibition of InlB-mediated F-actin rearrangements and bacterial entry. ARAP2 contains multiple functional domains, including a GTPase-activating protein (GAP) domain that antagonizes the GTPase Arf6 and a domain capable of binding the GTPase RhoA. Genetic data indicated roles for both the Arf GAP and RhoA binding domains in
Listeria
entry. Experiments involving Arf6 RNAi or a constitutively activated allele of Arf6 demonstrated that one of the ways in which ARAP2 promotes bacterial uptake is by restraining the activity of Arf6. Conversely, Rho activity was dispensable for
Listeria
internalization, suggesting that the RhoA binding domain in ARAP2 acts by engaging a host ligand other than Rho proteins. Collectively, our findings indicate that ARAP2 promotes InlB-mediated entry of
Listeria
, in part, by antagonizing the host GTPase Arf6.
Human Conjunctival Transcriptome Analysis Reveals the Prominence of Innate Defense inChlamydia trachomatisInfection
Authors: Natividad Angels , Freeman Tom C. , Jeffries David , Burton Matthew J. , Mabey David C. W. , Bailey Robin L. , Holland Martin J. 
Published: September 2010

ABSTRACTTrachoma is the leading infectious cause of blindness and is endemic in 52 countries. There is a critical need to further our understanding of the host response during disease and infection, as millions of individuals are still at risk of developing blinding sequelae. Infection of the conjunctival epithelial cells by the causative bacterium,Chlamydia trachomatis, stimulates an acute host response. The main clinical feature is a follicular conjunctivitis that is incompletely defined at the tissue-specific gene expression and molecular levels. To explore the features of disease and the response to infection, we measured host gene expression in conjunctival samples from Gambian children with active trachoma and healthy controls. Genome-wide expression and transcription network analysis identified signatures characteristic of the expected infiltrating immune cell populations, such as neutrophils and T/B lymphocytes. The expression signatures were also significantly enriched for genes in pathways which regulate NK cell activation and cytotoxicity, antigen processing and presentation, chemokines, cytokines, and cytokine receptors. The data suggest that in addition to polymorph and adaptive cellular responses, NK cells may contribute to a significant component of the conjunctival inflammatory response to chlamydial infection.
Small Molecule Inhibitors of LcrF, a
Yersinia pseudotuberculosis
Transcription Factor, Attenuate Virulence and Limit Infection in a Murine Pneumonia Model
Authors: Garrity-Ryan Lynne K. , Kim Oak K. , Balada-Llasat Joan-Miquel , Bartlett Victoria J. , Verma Atul K. , Fisher Michael L. , Castillo Cynthia , Songsungthong Warangkhana , Tanaka S. Ken , Levy Stuart B. , Mecsas Joan , Alekshun Michael N. 
Published: September 2010

ABSTRACT

LcrF (VirF), a transcription factor in the multiple adaptational response (MAR) family, regulates expression of the
Yersinia
type III secretion system (T3SS).
Yersinia pseudotuberculosis lcrF
-null mutants showed attenuated virulence in tissue culture and animal models of infection. Targeting of LcrF offers a novel, antivirulence strategy for preventing
Yersinia
infection. A small molecule library was screened for inhibition of LcrF-DNA binding in an
in vitro
assay. All of the compounds lacked intrinsic antibacterial activity and did not demonstrate toxicity against mammalian cells. A subset of these compounds inhibited T3SS-dependent cytotoxicity of
Y. pseudotuberculosis
toward macrophages
in vitro
. In a murine model of
Y. pseudotuberculosis
pneumonia, two compounds significantly reduced the bacterial burden in the lungs and afforded a dramatic survival advantage. The MAR family of transcription factors is well conserved, with members playing central roles in pathogenesis across bacterial genera; thus, the inhibitors could have broad applicability.
Analogous Telesensing Pathways Regulate Mating and Virulence in Two Opportunistic Human Pathogens
Authors: Bennett Richard J. , Dunny Gary M. 
Published: September 2010

ABSTRACT
Telesensing, or probing of the environment by the release of chemical messengers, plays a central role in the sexual programs of microbial organisms. Sex pheromones secreted by mating cells are sensed by potential partner cells and mediate cell-to-cell contact and the subsequent exchange of genetic material. Although the mechanisms used by bacterial and fungal species to promote genetic exchange are distinct, recent studies have uncovered surprising parallels between pheromone signaling in these species. In addition, it is now apparent that pheromone signaling not only controls sexual reproduction and genetic exchange but can also activate expression of potential virulence factors in diverse opportunistic pathogens.
A further examination of the nature of dispersive soils in Natal, South Africa
Authors: Bell F. G. , Walker D. J. H. 
Published: September 2010

Dispersive soils are found in the drier areas of Natal, in regions where the annual rainfall is less than 850 mm. They are derived from a variety of rock types. Dispersive soils deflocculate in the presence of relatively pure water to form colloidal suspensions and are therefore highly susceptible to erosion and piping. Dispersive erosion depends on the chemistry of the clay on the one hand, and the dissolved salts in the pore and eroding water on the other. The presence of exchangeable sodium on clay mineral surfaces is one of the main chemical factors contributing towards dispersive behaviour. Susceptibility to dispersion also is influenced by the total content of dissolved salts in the pore water.
The fabric of the soils was analysed by means of a scanning electron microscope. Turbostratic and flocculated structures were found in the clay material associated with low and high TDS contents respectively. The mineralogy, particle size distribution and consistency of these soils had little or no influence on dispersivity.
A series of physical and chemical tests was carried out in an attempt to assess dispersivity. Then an evaluation of the reliability of the results of these tests was undertaken by means of discriminant analysis. This indicated that the results of the crumb test, the pinhole test, the SAR value and the assessments provided by the CEC vs ESP and TDS vs % Na charts represented the best parameters to use in a rating system. Such a system is proposed to aid the recognition of dispersive soils.
Three-dimensional stability analysis of a coastal landslide at Hanover Point, Isle of Wight
Authors: Bromhead E.N. , Ibsen M-L. , Papanastassiou X. , Zemichael A.A. 
Published: September 2010

The applicability of 3-D slope stability analysis is discussed in the first part of the paper. A conclusion is drawn that 2-D analysis is often deficient in one or more respects, and often fails to model properly the true mechanics of landslides.
The paper describes the application of 3-D slope stability analysis using Hungr's Method of Columns to a small but active landslide in Wealden strata at Hanover Point on the SW coast of the Isle of Wight. The basal slide surface of this very small landslide follows a bedding plane. This bedding plane has components of dip both across the landslide and also into the slope. The shape of the slide mass is affected by the shape of the basal shear, but as the slide is also clearly prevented from moving in the direction of steepest dip (inland) by the confining effect of the embayment within which it is developing, the slide is a strong candidate for 3-D analysis.
Systematic analyses of the slide have been made using the Method of Columns, which is essentially a 3-D variant of the 2-D Method of Slices. By changing the assumed movement direction by a small amount between analyses, and covering all possibilities, it is demonstrated that there is a vector direction of movement that exhibits the least Factor of Safety. This vector direction is comparable to the actual movement direction observed in the field.
The paper draws conclusions as to the applicability of 3-D methods of analysis, and also concerning the evolution of bedding controlled landslides with dips into or out of the slope, when subject to strong marine attack and cliff retreat.
Angiopoietin-4 Promotes Glioblastoma Progression by Enhancing Tumor Cell Viability and Angiogenesis
Authors: Brunckhorst Melissa K. , Wang Hui , Lu Rong , Yu Qin 
Published: September 2010

Abstract
Glioblastoma multiforme (GBM) is a highly invasive and vascularized aggressive brain tumor. Less than 10% of GBM patients survive &gt;5 years after diagnosis. Angiogenesis plays an important role in GBM growth, and antiangiogenesis-based therapies have shown clinical efficacy for GBM patients. Unfortunately, therapeutic resistance often develops in these patients, suggesting that GBM cells are capable of switching their dependency on one proangiogenic signaling pathway to an alternative one. Therefore, it is important to identify novel angiogenic factors that play essential roles in tumor angiogenesis and GBM progression. Angiopoietins (Ang-1, Ang-2, and Ang-4) are the ligands of the Tie-2 receptor tyrosine kinase (RTK). The roles of Ang-1 and Ang-2 in tumor angiogenesis have been established. However, little is known about how Ang-4 affects tumor angiogenesis and GBM progression and the mechanism underlying its effects. In our current study, we establish that Ang-4 is upregulated in human GBM tissues and cells. We show that, like endothelial cells, human GBM cells express Tie-2 RTK. We first establish that Ang-4 promotes in vivo growth of human GBM cells by promoting tumor angiogenesis and directly activating extracellular signal-regulated kinase 1/2 (Erk1/2) in GBM cells. Our results establish the novel effects of Ang-4 on tumor angiogenesis and GBM progression and suggest that this pro-GBM effect of Ang-4 is mediated by promoting tumor angiogenesis and activating Erk1/2 kinase in GBM cells. Together, our results suggest that the Ang-4–Tie-2 functional axis is an attractive therapeutic target for GBM. Cancer Res; 70(18); 7283–93. ©2010 AACR.
Dacarbazine Treatment before Peptide Vaccination Enlarges T-Cell Repertoire Diversity of Melan-A–Specific, Tumor-Reactive CTL in Melanoma Patients
Authors: Palermo Belinda , Del Bello Duilia , Sottini Alessandra , Serana Federico , Ghidini Claudia , Gualtieri Novella , Ferraresi Virginia , Catricalà Caterina , Belardelli Filippo , Proietti Enrico , Natali Pier Giorgio , Imberti Luisa , Nisticò Paola 
Published: September 2010

AbstractCombination of chemotherapy and immunotherapy to increase the effectiveness of an antitumor immune response is currently regarded as an attractive antitumor strategy. In a pilot clinical trial, we have recently documented an increase of melanoma antigen A (Melan-A)–specific, tumor-reactive, long-lasting effector-memory CD8+ T cells after the administration of dacarbazine (DTIC) 1 day before peptide vaccination in melanoma patients. Global transcriptional analysis revealed a DTIC-induced activation of genes involved in the immune response and leukocyte activation. To identify the possible mechanisms underlying this improved immune response, we have compared the endogenous and the treatment-induced anti–Melan-A response at the clonal level in patients treated with the vaccine alone or with DTIC plus vaccine. We report a progressive widening of T-cell receptor (TCR) repertoire diversity, accompanied by high avidity and tumor reactivity, only in Melan-A–specific T-cell clones of patients treated with chemoimmunotherapy, with a trend toward longer survival. Differently, patients treated with vaccine alone showed a tendency to narrowing the TCR repertoire diversity, accompanied by a decrease of tumor lytic activity in one patient. Collectively, our findings indicate that DTIC plus vaccination shapes the TCR repertoire in terms of diversity and antitumor response, suggesting that this combined therapy could be effective in preventing melanoma relapse. Cancer Res; 70(18); 7084–92. ©2010 AACR.
The Neutrophil Elastase Inhibitor Elafin Triggers Rb-Mediated Growth Arrest and Caspase-Dependent Apoptosis in Breast Cancer
Authors: Caruso Joseph A. , Hunt Kelly K. , Keyomarsi Khandan 
Published: September 2010

Abstract
Elafin, an endogenous inhibitor of neutrophil elastase, is expressed in human mammary epithelial cells but is transcriptionally downregulated in breast cancer cells. We hypothesized that elafin may exert a tumor-suppressive activity in the context of breast cancer. In this study, we show that the retinoblastoma (Rb) pathway governs the antitumor properties of elafin. In breast cancer cells with functional Rb, the expression of elafin triggered Rb-dependent cell cycle arrest. Elafin also exhibited suppressive activity in breast cancer cell lines lacking Rb, but this was associated with an induction of caspase-3–dependent, p53-independent apoptotic cell death. Normal mammary epithelial cells were not affected by elafin. Collectively, these results argue that elafin mediates tumor-suppressive effects that are cytostatic or cytotoxic depending on the Rb status. Our findings suggest that elafin could be engineered as a therapeutic modality to treat breast cancer without toxicity to normal proliferating cells. Cancer Res; 70(18); 7125–36. ©2010 AACR.