bluuebunny/crossref_metadata_2025_split huggingface dataset:
Roles of
Candida albicans
Sfl1 in Hyphal Development
Authors: Li Yandong , Su Chang , Mao Xuming , Cao Fang , Chen Jiangye 
Published: August 2007

ABSTRACT

The ability to switch between different morphological forms is an important feature of
Candida albicans
and is relevant to its pathogenesis. Many conserved positive and negative transcription factors are involved in morphogenetic regulation of the two dimorphic fungi
Candida albicans
and
Saccharomyces cerevisiae.
In
S. cerevisiae
, the transcriptional repressor Sfl1 and the activator Flo8 function antagonistically in invasive and filamentous growth. We have previously reported that
Candida albicans
Flo8 is a transcription factor essential for hyphal development and virulence in
C. albicans
. To determine whether a similar negative factor exists in
C. albicans
, we identified
Candida albicans
Sfl1 as a functional homolog of the
S. cerevisiae sfl1
mutant. Sfl1 is a negative regulator of hyphal development in
C. albicans
. Deletion of
C. albicans SFL1
enhanced filamentous growth and hypha-specific gene expression in several media and at several growth temperatures. Overexpression of the
SFL1
led to a significant reduction of filament formation. Both deletion and overexpression of the
SFL1
attenuated virulence of
C. albicans
in a mouse model. Deleting
FLO8
in an
sfl1
/
sfl1
mutant completely blocked hyphal development in various growth conditions examined, suggesting that
C. albicans
Sfl1 may act as a negative regulator of filamentous growth by antagonizing Flo8 functions. We suggest that, similar to the case for
S. cerevisiae
, a combination of dual control by activation and repression of Flo8 and Sfl1 may contribute to the fine regulatory network in
C. albicans
morphogenesis responding to different environmental cues.
Distinguishing Acute from Chronic and Resolved Hepatitis C Virus (HCV) Infections by Measurement of Anti-HCV Immunoglobulin G Avidity Index
Authors: Klimashevskaya S. , Obriadina A. , Ulanova T. , Bochkova G. , Burkov A. , Araujo A. , Stramer Susan L. , Tobler Leslie H. , Busch Michael P. , Fields Howard A. 
Published: August 2007

ABSTRACTAn assay to measure avidity index (AI) was developed to diagnose incident hepatitis C virus (HCV) infections. The assay demonstrated an AI value statistically significantly lower in primary HCV infections than in chronic infections. When the assay was applied to past resolved infections, the difference in AI values was not as significant as the difference between incident and chronic infections. Lower AI values obtained in past resolved infections may be directly related to lower levels of immunoglobulin G anti-HCV in past resolved infections than in either new infections or chronic infections.
Differentiation of West Nile and St. Louis Encephalitis Virus Infections by Use of Noninfectious Virus-Like Particles with Reduced Cross-Reactivity
Authors: Roberson Jill A. , Crill Wayne D. , Chang Gwong-Jen J. 
Published: August 2007

ABSTRACT
Differential diagnosis of St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) infections can be complicated due to the high degree of cross-reactivity observed in most serodiagnostic assays. In an effort to provide a more specific diagnostic test, we developed virus-like particle (VLP) antigens with reduced cross-reactivity for both SLEV and WNV by identifying and mutating envelope protein amino acids within the cross-reactive epitopes of VLP expression plasmids. To determine the serodiagnostic discriminatory ability of the antigens with reduced cross-reactivity, a panel of 134 human serum samples collected predominately from North American patients with SLEV or WNV infections was used to evaluate the performance of these novel antigens in imunoglobulin M antibody-capture enzyme-linked immunosorbent assays. Positive/negative ratios and the resulting diagnostic classifications were compared between the mutant and the wild-type (WT) VLPs. The mutant VLP antigens were more specific, with higher positive predictive values and higher likelihood ratios than the WT VLP antigens. Both the SLEV and WNV mutant VLPs greatly reduced the observed cross-reactivity, significantly increasing the specificity and sensitivity of the assay. The use of these novel VLP antigens with reduced cross-reactivity in these serodiagnostic assays and others should lead to more accurate diagnoses of current infections, thereby reducing the need for time-consuming and cumbersome confirmatory plaque-reduction neutralization tests to differentiate between SLEV and WNV infections in North America.
Antimicrobial Resistance among Gram-Negative Bacilli Causing Infections in Intensive Care Unit Patients in the United States between 1993 and 2004
Authors: Lockhart Shawn R. , Abramson Murray A. , Beekmann Susan E. , Gallagher Gale , Riedel Stefan , Diekema Daniel J. , Quinn John P. , Doern Gary V. 
Published: August 2007

ABSTRACT

During the 12-year period from 1993 to 2004, antimicrobial susceptibility profiles of 74,394 gram-negative bacillus isolates recovered from intensive care unit (ICU) patients in United States hospitals were determined by participating hospitals and collected in a central location. MICs for 12 different agents were determined using a standardized broth microdilution method. The 11 organisms most frequently isolated were
Pseudomonas aeruginosa
(22.2%),
Escherichia coli
(18.8%),
Klebsiella pneumoniae
(14.2%),
Enterobacter cloacae
(9.1%),
Acinetobacter
spp. (6.2%),
Serratia marcescens
(5.5%),
Enterobacter aerogenes
(4.4%),
Stenotrophomonas maltophilia
(4.3%),
Proteus mirabilis
(4.0%),
Klebsiella oxytoca
(2.7%), and
Citrobacter freundii
(2.0%). Specimen sources included the lower respiratory tract (52.1%), urine (17.3%), and blood (14.2%). Rates of resistance to many of the antibiotics tested remained stable during the 12-year study period. Carbapenems were the most active drugs tested against most of the bacterial species.
E. coli
and
P. mirabilis
remained susceptible to most of the drugs tested. Mean rates of resistance to 9 of the 12 drugs tested increased with
Acinetobacter
spp. Rates of resistance to ciprofloxacin increased over the study period for most species. Ceftazidime was the only agent to which a number of species (
Acinetobacter
spp.,
C. freundii
,
E. aerogenes
,
K. pneumoniae
,
P. aeruginosa
, and
S. marcescens
) became more susceptible. The prevalence of multidrug resistance, defined as resistance to at least one extended-spectrum cephalosporin, one aminoglycoside, and ciprofloxacin, increased substantially among ICU isolates of
Acinetobacter
spp.,
P. aeruginosa
,
K. pneumoniae
, and
E. cloacae
.
Neuroinvasion of Fluorescein-Positive Monocytes in Acute Simian Immunodeficiency Virus Infection
Authors: Clay Candice C. , Rodrigues Denise S. , Ho Yan S. , Fallert Beth A. , Janatpour Kim , Reinhart Todd A. , Esser Ursula 
Published: August 2007

ABSTRACTMonocytes and macrophages play a central role in the pathogenesis of human immunodeficiency virus (HIV)-associated dementia. They represent prominent targets for HIV infection and are thought to facilitate viral neuroinvasion and neuroinflammatory processes. However, many aspects regarding monocyte brain recruitment in HIV infection remain undefined. The nonhuman primate model of AIDS is uniquely suited for examination of the role of monocytes in the pathogenesis of AIDS-associated encephalitis. Nevertheless, an approach to monitor cell migration from peripheral blood into the central nervous system (CNS) in primates had been lacking. Here, upon autologous transfer of fluorescein dye-labeled leukocytes, we demonstrate the trafficking of dye-positive monocytes into the choroid plexus stromata and perivascular spaces in the cerebra of rhesus macaques acutely infected with simian immunodeficiency virus between days 12 and 14 postinfection (p.i.). Dye-positive cells that had migrated expressed the monocyte activation marker CD16 and the macrophage marker CD68. Monocyte neuroinvasion coincided with the presence of the virus in brain tissue and cerebrospinal fluid and with the induction of the proinflammatory mediators CXCL9/MIG and CCL2/MCP-1 in the CNS. Prior to neuroinfiltration, plasma viral load levels peaked on day 11 p.i. Furthermore, the numbers of peripheral blood monocytes rapidly increased between days 4 and 8 p.i., and circulating monocytes exhibited increased functional capacity to produce CCL2/MCP-1. Our findings demonstrate acute monocyte brain infiltration in an animal model of AIDS. Such studies facilitate future examinations of the migratory profile of CNS-homing monocytes, the role of monocytes in virus import into the brain, and the disruption of blood-cerebrospinal fluid and blood-brain barrier functions in primates.
Induction of Epitope-Specific Neutralizing Antibodies against West Nile Virus
Authors: Oliphant Theodore , Nybakken Grant E. , Austin S. Kyle , Xu Qing , Bramson Jonathan , Loeb Mark , Throsby Mark , Fremont Daved H. , Pierson Theodore C. , Diamond Michael S. 
Published: August 2007

ABSTRACTPrevious studies have established that an epitope on the lateral ridge of domain III (DIII-lr) of West Nile virus (WNV) envelope (E) protein is recognized by strongly neutralizing type-specific antibodies. In contrast, an epitope against the fusion loop in domain II (DII-fl) is recognized by flavivirus cross-reactive antibodies with less neutralizing potential. Using gain- and loss-of-function E proteins and wild-type and variant WNV reporter virus particles, we evaluated the expression pattern and activity of antibodies against the DIII-lr and DII-fl epitopes in mouse and human serum after WNV infection. In mice, immunoglobulin M (IgM) antibodies to the DIII-lr epitope were detected at low levels at day 6 after infection. However, compared to IgG responses against other epitopes in DI and DII, which were readily detected at day 8, the development of IgG against DIII-lr epitope was delayed and did not appear consistently until day 15. This late time point is notable since almost all death after WNV infection in mice occurs by day 12. Nonetheless, at later time points, DIII-lr antibodies accumulated and comprised a significant fraction of the DIII-specific IgG response. In sera from infected humans, DIII-lr antibodies were detected at low levels and did not correlate with clinical outcome. In contrast, antibodies to the DII-fl were detected in all human serum samples and encompassed a significant percentage of the anti-E protein response. Our experiments suggest that the highly neutralizing DIII-lr IgG antibodies have little significant role in primary infection and that the antibody response of humans may be skewed toward the induction of cross-reactive, less-neutralizing antibodies.
A Heterologous DNA Prime-Venezuelan Equine Encephalitis Virus Replicon Particle Boost Dengue Vaccine Regimen Affords Complete Protection from Virus Challenge in Cynomolgus Macaques
Authors: Chen Lan , Ewing Dan , Subramanian Hemavathy , Block Karla , Rayner Jonathan , Alterson Kimberly D. , Sedegah Martha , Hayes Curtis , Porter Kevin , Raviprakash Kanakatte 
Published: August 2007

ABSTRACT
A candidate vaccine (D1ME-VRP) expressing dengue virus type 1 premembrane and envelope proteins in a Venezuelan equine encephalitis (VEE) virus replicon particle (VRP) system was constructed and tested in conjunction with a plasmid DNA vaccine (D1ME-DNA) expressing identical dengue virus sequences. Cynomolgus macaques were vaccinated with three doses of DNA (DDD), three doses of VRP (VVV group), or a heterologous DNA prime-VRP boost regimen (DDV) using two doses of DNA vaccine and a third dose of VRP vaccine. Four weeks after the final immunization, the DDV group produced the highest dengue virus type 1-specific immunoglobulin G antibody responses and virus-neutralizing antibody titers. Moderate T-cell responses were demonstrated only in DDD- and DDV-vaccinated animals. When vaccinated animals were challenged with live virus, all vaccination regimens showed significant protection from viremia. DDV-immunized animals were completely protected from viremia (mean time of viremia = 0 days), whereas DDD- and VVV-vaccinated animals had mean times of viremia of 0.66 and 0.75 day, respectively, compared to 6.33 days for the control group of animals.
White Spot Syndrome Virus Proteins and Differentially Expressed Host Proteins Identified in Shrimp Epithelium by Shotgun Proteomics and Cleavable Isotope-Coded Affinity Tag
Authors: Wu Jinlu , Lin Qingsong , Lim Teck Kwang , Liu Tiefei , Hew Choy-Leong 
Published: August 2007

ABSTRACT

Shrimp subcuticular epithelial cells are the initial and major targets of white spot syndrome virus (WSSV) infection. Proteomic studies of WSSV-infected subcuticular epithelium of
Penaeus monodon
were performed through two approaches, namely, subcellular fractionation coupled with shotgun proteomics to identify viral and host proteins and a quantitative time course proteomic analysis using cleavable isotope-coded affinity tags (cICATs) to identify differentially expressed cellular proteins. Peptides were analyzed by offline coupling of two-dimensional liquid chromatography with matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry. We identified 27, 20, and 4 WSSV proteins from cytosolic, nuclear, and membrane fractions, respectively. Twenty-eight unique WSSV proteins with high confidence (total ion confidence interval percentage [CI%], >95%) were observed, 11 of which are reported here for the first time, and 3 of these novel proteins were shown to be viral nonstructural proteins by Western blotting analysis. A first shrimp protein data set containing 1,999 peptides (ion score, ≥20) and 429 proteins (total ion score CI%, >95%) was constructed via shotgun proteomics. We also identified 10 down-regulated proteins and 2 up-regulated proteins from the shrimp epithelial lysate via cICAT analysis. This is the first comprehensive study of WSSV-infected epithelia by proteomics. The 11 novel viral proteins represent the latest addition to our knowledge of the WSSV proteome. Three proteomic data sets consisting of WSSV proteins, epithelial cellular proteins, and differentially expressed cellular proteins generated in the course of WSSV infection provide a new resource for further study of WSSV-shrimp interactions.
Production of Pseudoinfectious Yellow Fever Virus with a Two-Component Genome
Authors: Shustov Alexandr V. , Mason Peter W. , Frolov Ilya 
Published: August 2007

ABSTRACTApplication of genetically modified, deficient-in-replication flaviviruses that are incapable of developing productive, spreading infection is a promising means of designing safe and effective vaccines. Here we describe a two-component genome yellow fever virus (YFV) replication system in which each of the genomes encodes complete sets of nonstructural proteins that form the replication complex but expresses either only capsid or prM/E instead of the entire structural polyprotein. Upon delivery to the same cell, these genomes produce together all of the viral structural proteins, and cells release a combination of virions with both types of genomes packaged into separate particles. In tissue culture, this modified YFV can be further passaged at an escalating scale by using a high multiplicity of infection (MOI). However, at a low MOI, only one of the genomes is delivered into the cells, and infection cannot spread. The replicating prM/E-encoding genome produces extracellular E protein in the form of secreted subviral particles that are known to be an effective immunogen. The presented strategy of developing viruses defective in replication might be applied to other flaviviruses, and these two-component genome viruses can be useful for diagnostic or vaccine applications, including the delivery and expression of heterologous genes. In addition, the achieved separation of the capsid-coding sequence and the cyclization signal in the YFV genome provides a new means for studying the mechanism of the flavivirus packaging process.
Reactivation of Expression from Quiescent Herpes Simplex Virus Type 1 Genomes in the Absence of Immediate-Early Protein ICP0
Authors: Preston Chris M. 
Published: August 2007

ABSTRACT

Model systems have previously been developed in which herpes simplex virus (HSV) is retained in human fibroblasts in a nonreplicating state known as quiescence. The HSV type 1 (HSV-1) immediate-early (IE) protein ICP0, an important activator of gene expression, reactivates the quiescent genome and promotes the resumption of virus replication. Previous studies reported that infection with ICP0-null HSV-1 mutants fails to reactivate quiescent HSV, even when the mutant itself undergoes productive replication, leading to the hypothesis that quiescent genomes exist in a silent configuration in which they are shielded from
trans
-acting factors. I reinvestigated these findings, using HSV-1 mutants with lesions in the transcription activators VP16, ICP0, and ICP4 to establish quiescent infection at high efficiency. Superinfection with ICP0-null HSV-1 mutants at a low multiplicity of infection (MOI), so that individual plaques were formed, reactivated expression from the quiescent genome, demonstrating that the requirement for ICP0 is not absolute. The previously reported failure to observe reactivation by ICP0-null mutants was shown to be a consequence of either a low initial MOI or a high superinfecting MOI. Competition between viral genomes at the level of gene expression and virus replication, especially when ICP0 was absent, was demonstrated during reactivation and also during normal infection of human fibroblasts. The results show that the multiplicity-dependent phenotype of ICP0-null mutants limits the efficiency of reactivation at low MOIs and that competition between genomes occurs at high MOIs. The conclusion that quiescent HSV genomes are extensively silenced and intrinsically insensitive to
trans
-acting factors must be reevaluated.
Vaccines Based on Novel Adeno-Associated Virus Vectors Elicit Aberrant CD8+T-Cell Responses in Mice
Authors: Lin Jianping , Zhi Yan , Mays Lauren , Wilson James M. 
Published: August 2007

ABSTRACTWe recently discovered an expanded family of adeno-associated viruses (AAVs) that show promise as improved gene therapy vectors. In this study we evaluated the potential of vectors based on several of these novel AAVs as vaccine carriers for human immunodeficiency virus type 1 Gag. Studies with mice indicated that vectors based on AAV type 7 (AAV7), AAV8, and AAV9 demonstrate improved immunogenicity in terms of Gag CD8+T-cell and Gag antibody responses. The quality of these antigen-specific responses was evaluated in detail for AAV2/8 vectors and compared to results with an adenovirus vector expressing Gag (AdC7). AAV2/8 produced a vibrant CD8+T-cell effector response characterized by coexpression of gamma interferon and tumor necrosis factor alpha as well as in vivo cytolytic activity. No CD8+T-cell response generated by any of the AAVs was effectively boosted with AdC7, a result consistent with the finding of a relative lack of cells expressing interleukin-2 (IL-2) or a central memory phenotype at 3 months after the prime. The primary response to an AdC7 vaccine differed from that generated by AAVs in that the peak effector response evolved into populations of Gag-specific T cells expressing high levels of cytokines, including IL-2, and with effector memory and central memory phenotypes. A number of mechanisms could be considered to explain the aberrant activation of CD8+T cells by AAV, including insufficient inflammatory responses, CD4 help, and/or chronic antigen expression and T-cell exhaustion. Interestingly, the B-cell response to AAV-encoded Gag was quite vibrant and easily boosted with AdC7.
Nuclear Export of the Human Cytomegalovirus Tegument Protein pp65 Requires Cyclin-Dependent Kinase Activity and the Crm1 Exporter
Authors: Sanchez Veronica , Mahr Jeffrey A. , Orazio Nicole I. , Spector Deborah H. 
Published: August 2007

ABSTRACT
We have previously shown that treatment of human cytomegalovirus-infected cells with the cyclin-dependent kinase (cdk) inhibitor roscovitine has significant effects on several stages of the virus life cycle depending on the time of addition (V. Sanchez, A. K. McElroy, J. Yen, S. Tamrakar, C. L. Clark, R. A. Schwartz, and D. H. Spector, J. Virol. 78:11219-11232, 2004; V. Sanchez and D. Spector, J. Virol. 80:5886-5896, 2006). In this report, we add to these findings by demonstrating alterations in the phosphorylation and localization of pp65 (UL83) in cells treated with roscovitine. We observed that inhibition of cdk activity causes the retention of pp65 within the nucleus at late times postinfection. At the same time, we observed a change in the phosphorylation pattern of the protein. Interestingly, mutation of potential cdk phosphorylation sites did not affect the ability of pp65 to localize to the nucleus or to relocalize to the cytoplasm late in infection. However, we found that the cytoplasmic accumulation of pp65 late in infection was sensitive to the Crm1 inhibitor leptomycin B.
Stereotypes and Racial Images —White, Black and Yellow—
Authors: Mayovich Minako Kurokawa 
Published: August 2007

MUTUAL and self-perceptions of the racial images of the Whites, the Blacks and the Japanese Americans are studied among adult, college-student and school-children age-groups in California. For adults and college students, the Katz and Braly's adjective list was used, in which subjects were asked to choose five traits out of 84 to describe each racial group. Children were instructed to describe racial images in their own words. The hypothesis that the Whites occupying the dominant position are endowed with positive traits and the minority groups with negative traits was only partially supported. Another hypothese concerning the minority acceptance of the negative image ascribed by the dominant group, which was true in the 1930's, was invaild in this study. The Whites were portrayed as materialistic and pleasure-loving; the Blacks were musical, aggressive and straightforward; and the Japanese, industrious, ambitious, loyal to family and quiet.
The Multiple Recurrent Family Model in the Therapeutic Community
Authors: Lowental Uri 
Published: August 2007

An abridged version was presented at the First Scientific Congress of the Israel Psychiatric Association, Jerusalem, December 1972 Staff psychiatrist, head of Dept. C; Eitanim Psychiatric Hospital Jerusalem consulting psychiatrist at the Mevasseret-Zion Mental Health Clinic; candidiate at the Israel Institute for Psychoanalysis. I wish to express my thanks to H. Klein, M.D., Director of the Eitanim Hospital, and Senior Lecturer of Psychiatry at the Hebrew University, for his fruitful suggestions and encouragement.