bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of rpoB Mutations on Reduced Vancomycin Susceptibility in Staphylococcus aureus
Authors: Watanabe Yukiko , Cui Longzhu , Katayama Yuki , Kozue Kishii , Hiramatsu Keiichi 
Published: April 2011

ABSTRACT

Of 38 vancomycin-intermediate
Staphylococcus aureus
(VISA) clinical strains, 27 (71%) possessed a mutation(s) in
rpoB
encoding the β-subunit of RNA polymerase. Furthermore, 95.6% of the rifampin-resistant mutants obtained from 9 methicillin-resistant
S. aureus
(MRSA) clinical isolates showed decreased vancomycin susceptibilities. These data indicate the involvement of an
rpoB
mutation in VISA phenotype expression.
Molecular Characterization and Antimicrobial Susceptibility Testing of Escherichia coli Isolates from Patients with Urinary Tract Infections in 20 Chinese Hospitals
Authors: Cao Xiaoli , Cavaco Lina M. , Lv Yuan , Li Yun , Zheng Bo , Wang Pengyuan , Hasman Henrik , Liu Yucun , Aarestrup Frank M. 
Published: April 2011

ABSTRACT

A total of 222 urinary
Escherichia coli
isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspected extended-spectrum cephalosporinase (ESC) producers were examined for genes encoding cephalosporin resistance. Forty-three isolates harboring
bla
CTX-M-14
or
bla
CTX-M-15
were analyzed by pulsed-field gel electrophoresis (PFGE), and plasmids containing these genes were typed using PCR-based replicon typing (PBRT). Thirteen phylogroup B2
bla
CTX-M-14
- and
bla
CTX-M-15
-positive isolates were analyzed by multilocus sequence typing (MLST). A frequent occurrence of resistance (>46%) was observed toward cephalosporins, gentamicin, and fluoroquinolones. Among the 222 isolates, 4
qnrS1
, 4
qepA
, and 16
aac
(
6
′)
-Ib-cr
genes were confirmed. Four major phylogroups (A, B1, B2, and D) and nontypeable isolates (NTs) were found among the isolates, with phylogroup D (54%) being the most common phylogroup. A total of 110 (80%) of the 138 screened isolates harbored
bla
CTX-M
genes, with
bla
CTX-M-14
(71%) and
bla
CTX-M-15
(24%) being the most prevalent of these genes. Nine of the 13 CTX-M-15- or CTX-M-14-containing B2 isolates belonged to ST131. PFGE typing showed a high level of diversity, and plasmid analysis indicated a very large pool of different resistance plasmids mediating the spread of
bla
CTX-M
genes in mainland China. An equally very high frequency of resistance and equally high levels of diversity in phylogroups, PFGE types, and plasmids were observed among community- and hospital-acquired
E. coli
isolates, indicating the presence of a large reservoir in the community and a long-term spread of cephalosporin resistance in China.
Use of bexB To Detect the Capsule Locus in Haemophilus influenzae
Authors: Davis Gregg S. , Sandstedt Sara A. , Patel Mayuri , Marrs Carl F. , Gilsdorf Janet R. 
Published: April 2011

ABSTRACT

Haemophilus influenzae
strains are classified as typeable or nontypeable
H. influenzae
(NTHI) based upon the presence or absence of capsule. In addition to serotyping, which is subject to false-positive results, typeable strains can be identified through the detection of the capsular export gene
bexA
and one of six capsule-specific genes, but this method is resource intensive, especially in characterizing large numbers of strains. To address these challenges, we developed a
bexB
-based method to differentiate true NTHI strains from typeable strains. We validated a PCR-based method to detect
bexB
in 10 strains whose capsule status was well defined. Among 40 strains that were previously serotype positive in clinical microbiology laboratories, 5 lacked
bexA
,
bexB
, and capsule type-specific genes by PCR analysis and thus likely represent false-positive serotyping results. Among 94 additional otitis media, commensal, and serotype b-negative invasive strains, 85 were
bexA
and
bexB
negative and 9 contained either a complete or partial capsule locus, i.e., 8 were
bexA
and
bexB
positive and 1 was
bexA
negative but
bexB
positive. Finally, we adapted the method for use in a high-throughput DNA hybridization-based microarray method, which showed 98.75 and 97.5% concordance to the PCR methods for
bexA
and
bexB
, respectively. In addition,
bexB
showed 84% or greater nucleotide identity among strains containing the capsule locus. In this study, we demonstrate that
bexB
is a reliable proxy for the capsule locus and that its detection provides a simple and reliable method for differentiating strains that lack the entire capsule locus from those containing a partial or complete capsule locus.
Blood Cultures at Central Line Insertion in the Intensive Care Unit: Comparison with Peripheral Venipuncture
Authors: Stohl Sheldon , Benenson Shmuel , Sviri Sigal , Avidan Alexander , Block Colin , Sprung Charles L. , Levin Phillip D. 
Published: April 2011

ABSTRACT

Blood cultures are a key diagnostic test for intensive care unit (ICU) patients; however, contaminants complicate interpretations and lead to unnecessary antibiotic administration and costs. Indications for blood cultures and central venous catheter (CVC) insertions often overlap for ICU patients. Obtaining blood cultures under the strict sterile precautions utilized for CVC insertion might be expected to decrease culture contamination. This retrospective study compared the results of blood cultures taken at CVC insertion, at arterial line insertion, and from peripheral venipuncture in order to validate the advantage of CVC insertion cultures. Cultures from indwelling lines were excluded. Results of 14,589 blood cultures, including 2,736 (19%) CVC, 1,513 (10%) arterial line, and 10,340 (71%) peripheral cultures taken over 5.5 years in two ICUs (general and medical) were analyzed. CVC cultures were contaminated more frequently than arterial line or peripheral cultures (225/2,736 [8%] CVC, 48/1,513 [3%] arterial line, and 378/10,340 (4%) peripheral cultures [
P
< 0.001 for CVC versus peripheral and CVC versus arterial line cultures]). True pathogens were found more frequently in CVC insertion cultures (334/2,736 [12%] CVC, 155/1,513 [10%] arterial line, and 795/10,340 [8%] peripheral cultures [
P
< 0.001 for CVC versus peripheral cultures;
P
= 0.055 for CVC versus arterial line cultures;
P
< 0.001 for peripheral versus arterial line cultures]). Contamination and true-positive rates were similar for culture sets from the two ICUs for each given culture source. Despite superior sterile precautions, cultures taken at the time of central line insertion had a higher contamination rate than did either peripheral or arterial line blood cultures. This may be related to the increased manipulations required for CVC insertion.
Ubiquitin-Specific Peptidase 20 Targets TRAF6 and Human T Cell Leukemia Virus Type 1 Tax To Negatively Regulate NF-κB Signaling
Authors: Yasunaga Junichiro , Lin Frank C. , Lu Xiongbin , Jeang Kuan-Teh 
Published: April 2011

ABSTRACT
NF-κB plays a key role in innate and acquired immunity. Its activity is regulated through intricate signaling networks. Persistent or excessive activation of NF-κB induces diseases, such as autoimmune disorders and malignant neoplasms. Infection by human T cell leukemia virus type 1 (HTLV-1) causes a fatal hematopoietic malignancy termed adult T cell leukemia (ATL). The HTLV-1 viral oncoprotein Tax functions pivotally in leukemogenesis through its potent activation of NF-κB. Recent findings suggest that protein ubiquitination is crucial for proper regulation of NF-κB signaling and for Tax activity. Here, we report that ubiquitin-specific peptidase USP20 deubiquitinates TRAF6 and Tax and suppresses interleukin 1β (IL-1β)- and Tax-induced NF-κB activation. Our results point to USP20 as a key negative regulator of Tax-induced NF-κB signaling.
Strong Human Endogenous Retrovirus-Specific T Cell Responses Are Associated with Control of HIV-1 in Chronic Infection
Authors: SenGupta Devi , Tandon Ravi , Vieira Raphaella G. S. , Ndhlovu Lishomwa C. , Lown-Hecht Rachel , Ormsby Christopher E. , Loh Liyen , Jones R. Brad , Garrison Keith E. , Martin Jeffrey N. , York Vanessa A. , Spotts Gerald , Reyes-Terán Gustavo , Ostrowski Mario A. , Hecht Frederick M. , Deeks Steven G. , Nixon Douglas F. 
Published: April 2011

ABSTRACT

Eight percent of the human genome is composed of human endogenous retroviruses (HERVs), which are thought to be inactive remnants of ancient infections. Previously, we showed that individuals with early HIV-1 infection have stronger anti-HERV T cell responses than uninfected controls. In this study, we investigated whether these responses persist in chronic HIV-1 infection and whether they have a role in the control of HIV-1. Peripheral blood mononuclear cells (PBMCs) from 88 subjects diagnosed with HIV-1 infection for at least 1 year (median duration of diagnosis, 13 years) were tested for responses against HERV peptides in gamma interferon (IFN-γ) enzyme immunospot (ELISPOT) assays. Individuals who control HIV-1 viremia without highly active antiretroviral therapy (HAART) had stronger and broader HERV-specific T cell responses than HAART-suppressed patients, virologic noncontrollers, immunologic progressors, and uninfected controls (
P
< 0.05 for each pairwise comparison). In addition, the magnitude of the anti-HERV T cell response was inversely correlated with HIV-1 viral load (
r
2
= 0.197,
P
= 0.0002) and associated with higher CD4
+
T cell counts (
r
2
= 0.072,
P
= 0.027) in untreated patients. Flow cytometric analyses of an HLA-B51-restricted CD8
+
HERV response in one HIV-1-infected individual revealed a less activated and more differentiated phenotype than that stimulated by a homologous HIV-1 peptide. HLA-B51 tetramer dual staining within this individual confirmed two different T cell populations corresponding to these HERV and HIV-1 epitopes, ruling out cross-reactivity. These findings suggest a possible role for anti-HERV immunity in the control of chronic HIV-1 infection and provide support for a larger effort to design an HIV-1 vaccine that targets conserved antigens such as HERV.
Shifting Hierarchies of Interleukin-10-Producing T Cell Populations in the Central Nervous System during Acute and Persistent Viral Encephalomyelitis
Authors: Puntambekar Shweta S. , Bergmann Cornelia C. , Savarin Carine , Karp Christopher L. , Phares Timothy W. , Parra Gabriel I. , Hinton David R. , Stohlman Stephen A. 
Published: April 2011

ABSTRACTInterleukin-10 (IL-10) mRNA is rapidly upregulated in the central nervous system (CNS) following infection with neurotropic coronavirus and remains elevated during persistent infection. Infection of transgenic IL-10/green fluorescent protein (GFP) reporter mice revealed that CNS-infiltrating T cells were the major source of IL-10, with minimal IL-10 production by macrophages and resident microglia. The proportions of IL-10-producing cells were initially similar in CD8+and CD4+T cells but diminished rapidly in CD8+T cells as the virus was controlled. Overall, the majority of IL-10-producing CD8+T cells were specific for the immunodominant major histocompatibility complex (MHC) class I epitope. Unlike CD8+T cells, a large proportion of CD4+T cells within the CNS retained IL-10 production throughout persistence. Furthermore, elevated frequencies of IL-10-producing CD4+T cells in the spinal cord supported preferential maintenance of IL-10 production at the site of viral persistence and tissue damage. IL-10 was produced primarily by the CD25+CD4+T cell subset during acute infection but prevailed in CD25−CD4+T cells during the transition to persistent infection and thereafter. Overall, these data demonstrate significant fluidity in the T-cell-mediated IL-10 response during viral encephalitis and persistence. While IL-10 production by CD8+T cells was limited primarily to the time of acute effector function, CD4+T cells continued to produce IL-10 throughout infection. Moreover, a shift from predominant IL-10 production by CD25+CD4+T cells to CD25−CD4+T cells suggests that a transition to nonclassical regulatory T cells precedes and is retained during CNS viral persistence.
Evaluation of the Newcastle Disease Virus F and HN Proteins in Protective Immunity by Using a Recombinant Avian Paramyxovirus Type 3 Vector in Chickens
Authors: Kumar Sachin , Nayak Baibaswata , Collins Peter L. , Samal Siba K. 
Published: April 2011

ABSTRACT
Newcastle disease virus (NDV) belongs to serotype 1 of the avian paramyxoviruses (APMV-1) and causes severe disease in chickens. Current live attenuated NDV vaccines are not fully satisfactory. An alternative is to use a viral vector vaccine that infects chickens but does not cause disease. APMV serotype 3 infects a wide variety of avian species but does not cause any apparent disease in chickens. In this study, we constructed a reverse-genetics system for recovery of infectious APMV-3 strain Netherlands from cloned cDNAs. Two recombinant viruses, rAPMV3-F and rAPMV3-HN, were generated expressing the NDV fusion (F) and hemagglutinin-neuraminidase (HN) proteins, respectively, from added genes. These viruses were used to immunize 2-week-old chickens by the oculonasal route in order to evaluate the contribution of each protein to the induction of NDV-specific neutralizing antibodies and protective immunity. Each virus induced high titers of NDV-specific hemagglutination inhibition and serum neutralizing antibodies, but the response to F protein was greater. Protective immunity was evaluated by challenging the immunized birds 21 days later with virulent NDV via the oculonasal, intramuscular, or intravenous route. With oculonasal or intramuscular challenge, all three recombinant viruses (rAPMV3, rAPMV3-F, and rAPMV3-HN) were protective, while all unvaccinated birds succumbed to death. These results indicated that rAPMV3 alone can provide cross-protection against NDV challenge. However, with intravenous challenge, birds immunized with rAPMV3 were not protected, whereas birds immunized with rAPMV3-F alone or in combination with rAPMV3-HN were completely protected, and birds immunized with rAPMV3-HN alone were partially protected. These results indicate that the NDV F and HN proteins are independent neutralization and protective antigens, but the contribution by F is greater. rAMPV3 represents an avirulent vaccine vector that can be used against NDV and other poultry pathogens.
RAB11A Is Essential for Transport of the Influenza Virus Genome to the Plasma Membrane
Authors: Eisfeld Amie J. , Kawakami Eiryo , Watanabe Tokiko , Neumann Gabriele , Kawaoka Yoshihiro 
Published: April 2011

ABSTRACT
Influenza A virus assembly is a complex process that requires the intersection of pathways involved in transporting viral glycoproteins, the matrix protein, and viral genomes, incorporated in the viral ribonucleoprotein (vRNP) complex, to plasma membrane sites of virion formation. Among these virion components, the mechanism of vRNP delivery is the most incompletely understood. Here, we reveal a functional relationship between the cellular Rab11 GTPase isoform, RAB11A, and vRNPs and show that RAB11A is indispensable for proper vRNP transport to the plasma membrane. Using an immunofluorescence-based assay with a monoclonal antibody that recognizes nucleoprotein in the form of vRNP, we demonstrate association between RAB11A and vRNPs at all stages of vRNP cytoplasmic transport. Abrogation of RAB11A expression through small interfering RNA (siRNA) treatment or disruption of RAB11A function by overexpression of dominant negative or constitutively active proteins caused aberrant vRNP intracellular accumulation, retention in the perinuclear region, and lack of accumulation at the plasma membrane. Complex formation between RAB11A and vRNPs was further established biochemically. Our results uncover a critical host factor with an essential contribution to influenza virus genome delivery and reveal a potential role for RAB11A in the transport of ribonucleoprotein cargo.
Sulfolobus Turreted Icosahedral Virus c92 Protein Responsible for the Formation of Pyramid-Like Cellular Lysis Structures
Authors: Snyder Jamie C. , Brumfield Susan K. , Peng Nan , She Qunxin , Young Mark J. 
Published: April 2011

ABSTRACT

Host cells infected by
Sulfolobus
turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in
Archaea
and appears to be distinct from the holin/endolysin system described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host
Sulfolobus solfataricus
. Overexpression of STIV open reading frame (ORF) c92 in
S. solfataricus
alone is sufficient to produce the pyramid-like lysis structures in cells. Gene disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures.
Helper Component Proteinase of the Genus Potyvirus Is an Interaction Partner of Translation Initiation Factors eIF(iso)4E and eIF4E and Contains a 4E Binding Motif
Authors: Ala-Poikela Marjo , Goytia Elisa , Haikonen Tuuli , Rajamäki Minna-Liisa , Valkonen Jari P. T. 
Published: April 2011

ABSTRACT

The multifunctional helper component proteinase (HCpro) of potyviruses (genus
Potyvirus
;
Potyviridae
) shows self-interaction and interacts with other potyviral and host plant proteins. Host proteins that are pivotal to potyvirus infection include the eukaryotic translation initiation factor eIF4E and the isoform eIF(iso)4E, which interact with viral genome-linked protein (VPg). Here we show that HCpro of
Potato virus A
(PVA) interacts with both eIF4E and eIF(iso)4E, with interactions with eIF(iso)4E being stronger, as judged by the data of a yeast two-hybrid system assay. A bimolecular fluorescence complementation assay on leaves of
Nicotiana benthamiana
showed that HCpro from three potyviruses (PVA,
Potato virus Y
, and
Tobacco etch virus
) interacted with the eIF(iso)4E and eIF4E of tobacco (
Nicotiana tabacum
); interactions with eIF(iso)4E and eIF4E of potato (
Solanum tuberosum
) were weaker. In PVA-infected cells, interactions between HCpro and tobacco eIF(iso)4E were confined to round structures that colocalized with 6K2-induced vesicles. Point mutations introduced to a 4E binding motif identified in the C-terminal region of HCpro debilitated interactions of HCpro with translation initiation factors and were detrimental to the virulence of PVA in plants. The 4E binding motif conserved in HCpro of potyviruses and HCpro-initiation factor interactions suggest new roles for HCpro and/or translation factors in the potyvirus infection cycle.
RNA Structural Domains in Noncoding Regions of the Foot-and-Mouth Disease Virus Genome Trigger Innate Immunity in Porcine Cells and Mice
Authors: Rodríguez-Pulido Miguel , Borrego Belén , Sobrino Francisco , Sáiz Margarita 
Published: April 2011

ABSTRACT

The induction of type I interferons (alpha/beta interferon [IFN-α/β]) in response to viral infection is a crucial step leading to the antiviral state in the host. Viruses produce double-stranded RNA (dsDNA) during their replication cycle that is sensed as nonself by host cells through different receptors. A signaling cascade then is activated to block viral replication and spread. Foot-and-mouth disease virus (FMDV) is a picornavirus that is highly sensitive to IFN, and it causes one of the world's most important animal diseases. In this study, we showed the ability of structural domains predicted to enclose stable dsRNA regions in the 5′- and 3′-noncoding regions (NCRs) of the FMDV genome to trigger an IFN-α/β response in porcine kidney cultured cells and newborn mice. These RNAs, generated by
in vitro
transcription, were able to stimulate IFN-β transcription and induce an antiviral state in SK-6 cells. The induction levels elicited by the different NCR RNAs were compared. Among them, the 3′NCR was identified as a potent IFN activator, and the features in this region involved in signaling have been analyzed. To address whether the FMDV NCR transcripts were able to trigger the innate immune response
in vivo
, Swiss suckling mice were inoculated intraperitoneally with the RNAs. All transcripts induced the innate response in transfected animals, measured as IFN-α/β protein levels, antiviral activity in sera, and reduced susceptibility to FMDV infection. Our work provides new insight into innate responses against FMDV and identifies these small noninfectious RNA molecules as potential adjuvants for vaccine improvement and antiviral strategies against picornaviruses.
Functional Macroautophagy Induction by Influenza A Virus without a Contribution to Major Histocompatibility Complex Class II-Restricted Presentation
Authors: Comber Joseph D. , Robinson Tara M. , Siciliano Nicholas A. , Snook Adam E. , Eisenlohr Laurence C. 
Published: April 2011

ABSTRACTMajor histocompatibility complex (MHC) class II-presented peptides can be derived from both exogenous (extracellular) and endogenous (biosynthesized) sources of antigen. Although several endogenous antigen-processing pathways have been reported, little is known about their relative contributions to global CD4+T cell responses against complex antigens. Using influenza virus for this purpose, we assessed the role of macroautophagy, a process in which cytosolic proteins are delivered to the lysosome byde novovesicle formation and membrane fusion. Influenza infection triggered productive macroautophagy, and autophagy-dependent presentation was readily observed with model antigens that naturally traffic to the autophagosome. Furthermore, treatments that enhance or inhibit macroautophagy modulated the level of presentation from these model antigens. However, validated enzyme-linked immunospot (ELISpot) assays of influenza-specific CD4+T cells from infected mice using a variety of antigen-presenting cells, including primary dendritic cells, revealed no detectable macroautophagy-dependent component. In contrast, the contribution of proteasome-dependent endogenous antigen processing to the global influenza CD4+response was readily appreciated. The contribution of macroautophagy to the MHC class II-restricted response may vary depending upon the pathogen.
Varicella-Zoster Virus (VZV) Infection of Neurons Derived from Human Embryonic Stem Cells: Direct Demonstration of Axonal Infection, Transport of VZV, and Productive Neuronal Infection
Authors: Markus Amos , Grigoryan Sergei , Sloutskin Anna , Yee Michael B. , Zhu Hua , Yang In Hong , Thakor Nitish V. , Sarid Ronit , Kinchington Paul R. , Goldstein Ronald S. 
Published: April 2011

ABSTRACT
Study of the human neurotrophic herpesvirus varicella-zoster virus (VZV) and of its ability to infect neurons has been severely limited by strict viral human tropism and limited availability of human neurons for experimentation. Human embryonic stem cells (hESC) can be differentiated to all the cell types of the body including neurons and are therefore a potentially unlimited source of human neurons to study their interactions with human neurotropic viruses. We report here reproducible infection of hESC-derived neurons by cell-associated green fluorescent protein (GFP)-expressing VZV. hESC-derived neurons expressed GFP within 2 days after incubation with mitotically inhibited MeWo cells infected with recombinant VZV expressing GFP as GFP fusions to VZV proteins or under an independent promoter. VZV infection was confirmed by immunostaining for immediate-early and viral capsid proteins. Infection of hESC-derived neurons was productive, resulting in release into the medium of infectious virions that appeared fully assembled when observed by electron microscopy. We also demonstrated, for the first time, VZV infection of axons and retrograde transport from axons to neuronal cell bodies using compartmented microfluidic chambers. The use of hESC-derived human neurons in conjunction with fluorescently tagged VZV shows great promise for the study of VZV neuronal infection and axonal transport and has potential for the establishment of a model for VZV latency in human neurons.