bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorous availability influences the dissolution of apatite by soil fungi
Authors: ROSLING A. , SUTTLE K. B. , JOHANSSON E. , VAN HEES P. A. W. , BANFIELD J. F. 
Published: April 2007

ABSTRACTApatite (Ca10(PO4)6(OH,F,Cl)2) is the primary inorganic source of phosphorus in the biosphere. Soil fungi are known to increase plant‐available phosphorus by promoting dissolution of various phosphate minerals. Yet no apatite dissolution studies exist using fungi as weathering agents, and regulation of fungal weathering activity in response to different levels of phosphorus availability is largely unknown.Fungi were isolated from a grassland soil in northern California. Three pathways of tri‐calcium phosphate (Ca3(PO4)2) (TCP) dissolution in liquid culture were identified among biogeochemically active fungi: (1) acidification (pH 3.3 ± 0.16), (2) moderate acidification (pH 4.9 ± 0.11) and (3) no acidification. Isolates representing pathway 1 and 2 were Zygomycetes in the order of Mucorales. All non‐acidifying isolates in pathway 3 were Ascomycetes and cleared the media by altering TCP into hydroxyapatite (Ca10(PO4)6(OH)2) and sequestering it within mycelial spheres. One isolate representing each pathway was used in fluorapatite dissolution experiments either with the fungi present or under abiotic conditions using cell‐free liquid media conditioned by fungal growth at different phosphorus and calcium availabilities.Both Mucorales isolates acidify their substrate when growing in the presence of phosphorus. Mucorales exudates were mainly oxalic acid, and conditioned cell‐free media with phosphorus induced fluorapatite dissolution at a rate of 10−0.9±0.14 and 10−1.2±0.22 µmol P m−2 s−1. The ascomycete isolate on the other hand, induced fluorapatite dissolution at a rate of 10−1.1±0.05 µmol P m−2 s−1 by lowering the pH of the media under phosphorus‐limited conditions, without producing significant amounts of low molecular weight organic acids (LMWOAs). Oxalate strongly etches fluorapatite along channels parallel to [001], forming needle‐like features, while exudates from the ascomycete‐induced surface rounding. We conclude that while LMWOAs are well‐studied weathering agents, these do not appear to be produced by fungi in response to phosphorus‐limiting growth conditions.
Improved Immunogenicity of a Vaccination Regimen Combining a DNA Vaccine Encoding
Brucella melitensis
Outer Membrane Protein 31 (Omp31) and Recombinant Omp31 Boosting
Authors: Cassataro Juliana , Velikovsky Carlos A. , Bruno Laura , Estein Silvia M. , de la Barrera Silvia , Bowden Raúl , Fossati Carlos A. , Giambartolomei Guillermo H. 
Published: April 2007

ABSTRACT

In the present study, we report an attempt to improve the immunogenicity of the Omp31 antigen by a DNA prime-protein boost immunization regimen. We immunized BALB/c mice with an Omp31 DNA vaccine (pCIOmp31) followed by boosting with recombinant Omp31 (rOmp31) in incomplete Freund's adjuvant and characterized the resulting immune responses and the protective efficacy against
Brucella ovis
and
B. melitensis
infection. Immunoglobulin G1 (IgG1) and IgG2a titers were higher in sera from pCIOmp31/rOmp31-immunized mice than in sera from mice immunized with pCIOmp31 or rOmp31 alone. Splenocytes from pCIOmp31/rOmp31-immunized mice produced significantly higher levels of gamma interferon than did those from mice given rOmp31 alone. In contrast, interleukin 2 (IL-2) production levels were comparable between the two groups of immunized mice. Cells from all immunized mice produced undetectable levels of IL-4. Notably, rOmp31 stimulated IL-10 production in the pCIOmp31/rOmp31-immunized group but not in the pCIOmp31- or rOmp31-immunized group. Although the prime-boost regimen induced specific cytotoxic responses, these responses could not reach the levels achieved by the pCIOmp31 immunization. In conclusion, pCIOmp31 priming followed by rOmp31 boosting led to moderately improved protection against a challenge with
B. ovis
or
B. melitensis
.
Multicenter Evaluation of a New Disk Agar Diffusion Method for Susceptibility Testing of Filamentous Fungi with Voriconazole, Posaconazole, Itraconazole, Amphotericin B, and Caspofungin
Authors: Espinel-Ingroff A. , Arthington-Skaggs B. , Iqbal N. , Ellis D. , Pfaller M. A. , Messer S. , Rinaldi M. , Fothergill A. , Gibbs D. L. , Wang A. 
Published: April 2007

ABSTRACT

The purpose of this study was to correlate inhibition zone diameters, in millimeters (agar diffusion disk method), with the broth dilution MICs or minimum effective concentrations (MECs) (CLSI M38-A method) of five antifungal agents to identify optimal testing guidelines for disk mold testing. The following disk diffusion testing parameters were evaluated for 555 isolates of the molds
Absidia corymbifera
,
Aspergillus
sp. (five species),
Alternaria
sp.,
Bipolaris spicifera
,
Fusarium
sp. (three species),
Mucor
sp. (two species),
Paecilomyces lilacinus
,
Rhizopus
sp. (two species), and
Scedosporium
sp. (two species): (i) two media (supplemented Mueller-Hinton agar [2% dextrose and 0.5 μg/ml methylene blue] and plain Mueller-Hinton [MH] agar), (ii) three incubation times (16 to 24, 48, and 72 h), and (iii) seven disks (amphotericin B and itraconazole 10-μg disks, voriconazole 1- and 10-μg disks, two sources of caspofungin 5-μg disks [BBL and Oxoid], and posaconazole 5-μg disks). MH agar supported better growth of all of the species tested (24 to 48 h). The reproducibility of zone diameters and their correlation with either MICs or MECs (caspofungin) were superior on MH agar (91 to 100% versus 82 to 100%;
R
, 0.71 to 0.93 versus 0.53 to 0.96 for four of the five agents). Based on these results, the optimal testing conditions for mold disk diffusion testing were (i) plain MH agar; (ii) incubation times of 16 to 24 h (zygomycetes), 24 h (
Aspergillus fumigatus
,
A. flavus
, and
A. niger
), and 48 h (other species); and (iii) the posaconazole 5-μg disk, voriconazole 1-μg disk, itraconazole 10-μg disk (for all except zygomycetes), BBL caspofungin 5-μg disk, and amphotericin B 10-μg (zygomycetes only).
Prevalence of PCR Ribotypes among
Clostridium difficile
Isolates from Pigs, Calves, and Other Species
Authors: Keel Kevin , Brazier Jon S. , Post Karen W. , Weese Scott , Songer J. Glenn 
Published: April 2007

ABSTRACT

PCR ribotypes were obtained for 144
Clostridium difficile
isolates from neonatal pigs. Porcine isolates comprised four PCR ribotypes, but one, ribotype 078, predominated (83%). This was also the most common ribotype (94%) among 33 calf isolates but was rarely identified in other species.
Evaluation of Three Molecular Assays for Rapid Identification of Methicillin-Resistant
Staphylococcus aureus
Authors: Francois Patrice , Bento Manuela , Renzi Gesuele , Harbarth Stephan , Pittet Didier , Schrenzel Jacques 
Published: April 2007

ABSTRACT

One home-developed assay and two commercial assays for the rapid identification of methicillin-resistant
Staphylococcus aureus
(MRSA) were compared by use of a collection of clinical isolates displaying highly diverse genetic backgrounds. Our results suggest that users of
orfX
-staphylococcal cassette chromosome
mec
-based assays should repeatedly monitor the local epidemiology to minimize the risks of detection bias and the omission of emerging MRSA clones.
Comparison of Tests for Detection of β-Lactamase-Producing Staphylococci
Authors: Pitkälä A. , Salmikivi L. , Bredbacka P. , Myllyniemi A.-L. , Koskinen M. T. 
Published: April 2007

ABSTRACT
Penicillin resistance identification tests are important in veterinary medicine. Six enzyme assays and a PCR test were compared for the detection of β-lactamase production or the β-lactamase gene in 175 staphylococcal isolates. We conclude that the PCR test and two nitrocefin-based assays can be recommended for routine clinical use.
Comparison of the Phenotyping Methods ID 32E and VITEK 2 Compact GN with 16S rRNA Gene Sequencing for the Identification of
Enterobacter sakazakii
Authors: Fanjat Nadège , Leclercq Alexandre , Joosten Han , Robichon Denis 
Published: April 2007

ABSTRACT

A total of 34 isolates (28
Enterobacter sakazakii
and 6
Enterobacteriaceae
) from infant formulae, milk powder, and the production environment of milk powder factories were identified using ID 32E and VITEK 2 compact GN systems (bioMérieux, France). The ID 32E version 3.0 and VITEK 2 compact GN version 01.01b correctly identified 100% (28) of the
Enterobacter sakazakii
isolates tested, whereas the previous software version 2.0 for ID 32E showed only 71.4% correct results. None of the non-
E. sakazakii
isolates tested were misidentified as
E. sakazakii
with either of the identification systems used.
Comparative Genomics of Canadian Epidemic Lineages of Methicillin-Resistant
Staphylococcus aureus
Authors: Christianson Sara , Golding George R. , Campbell Jennifer , Mulvey Michael R. 
Published: April 2007

ABSTRACT

Methicillin-resistant
Staphylococcus aureus
(MRSA) is a pathogen that has disseminated throughout Canadian hospitals and communities. Pulsed-field gel electrophoresis of over 9,300 MRSA isolates obtained from the Canadian Nosocomial Infection Surveillance Program has identified 10 epidemic strain types in Canada (CMRSA1 to CMRSA10). In an attempt to determine specific genetic factors that have contributed to their high prevalence in community and/or hospital settings, the genomic content of representative isolates for each of the 10 Canadian epidemic types was compared using comparative genomic hybridizations. Comparison of the community-associated Canadian epidemic isolates (CMRSA7 and CMRSA10) with the hospital-associated Canadian epidemic isolates revealed one open reading frame (ORF) (SACOL0046) encoding a putative protein belonging to a metallo-beta-lactamase family, which was present only in the community-associated Canadian epidemic isolates. A more restricted comparison involving only the most common hospital-associated Canadian epidemic isolates (CMRSA1 and CMRSA2) with the community-associated Canadian epidemic isolates did reveal additional factors that might be contributing to their prevalence in the community and hospital settings, which included ORFs encoding potential virulence factors involved in capsular biosynthesis, serine proteases, epidermin, adhesion factors, regulatory functions, leukotoxins, and exotoxins.
Genetic Relatedness of
Streptococcus pneumoniae
Isolates from Paired Blood and Respiratory Specimens
Authors: Harrell L. J. , Sharps S. K. , Bean R. A. , Reller L. B. 
Published: April 2007

ABSTRACT

To assess the relatedness of
Streptococcus pneumoniae
isolates recovered concurrently from blood and respiratory tract specimens from patients with pneumonia, we analyzed 24 paired isolates by pulsed-field gel electrophoresis (PFGE), serotyping, and antimicrobial susceptibility testing. PFGE, serotype, and/or susceptibility patterns were identical for 22 of 24 pairs. Susceptibility results for blood isolates should guide therapy.
Differential Outcome of Tolerance Induction in Naive versus Activated Theiler's Virus Epitope-Specific CD8+Cytotoxic T Cells
Authors: Getts Meghann Teague , Kim Byung S. , Miller Stephen D. 
Published: April 2007

ABSTRACTTolerance induced by the intravenous injection of peptide-pulsed, ethylene carbodiimide (ECDI)-fixed splenic antigen-presenting cells (Ag-SP) is a safe and effective method of inducing specific unresponsiveness in CD4+T cells for the prevention and treatment of a variety of autoimmune diseases. We determined whether Ag-SP tolerance could also be used to tolerize CD8+T cells. We show in the Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease model of multiple sclerosis that CD8+T cells specific for both dominant and subdominant epitopes can be rendered tolerant. Interestingly, although virus clearance was delayed, lack of the virus-specific cytotoxic T-lymphocyte response did not result in the conversion of normally TMEV-resistant C57BL/6 mice to a susceptible phenotype. Importantly, we found that Ag-SP tolerance may not be a practical treatment for human diseases in which CD8+T cells play a major role in pathogenesis, as tolerance induction in mice previously infected with TMEV led to a severe, often fatal reaction.
Mucosal Innate Immune Response Associated with a Timely Humoral Immune Response and Slower Disease Progression after Oral Transmission of Simian Immunodeficiency Virus to Rhesus Macaques
Authors: Milush Jeffrey M. , Stefano-Cole Kelly , Schmidt Kimberli , Durudas Andre , Pandrea Ivona , Sodora Donald L. 
Published: April 2007

ABSTRACT

Mucosal transmission is the predominant mode of human immunodeficiency virus (HIV) infection worldwide, and the mucosal innate interferon response represents an important component of the earliest host response to the infection. Our goal here was to assess the changes in mRNA expression of innate mucosal genes after oral simian immunodeficiency virus (SIV) inoculation of rhesus macaques (
Macaca mulatta
) that were followed throughout their course of disease progression. The SIV plasma viral load was highest in the macaque that progressed rapidly to simian AIDS (99 days) and lowest in the macaque that progressed more slowly (>700 days). The mRNA levels of six innate/effector genes in the oral mucosa indicated that slower disease progression was associated with increased expression of these genes. This distinction was most evident when comparing the slowest-progressing macaque to the intermediate and rapid progressors. Expression levels of alpha and gamma interferons, the antiviral interferon-stimulated gene product 2′-5′ oligoadenylate synthetase (OAS), and the chemokines CXCL9 and CXCL10 in the slow progressor were elevated at each of the three oral mucosal biopsy time points examined (day 2 to 4, 14 to 21, and day 70 postinfection). In contrast, the more rapidly progressing macaques demonstrated elevated levels of these cytokine/chemokine mRNA at lymph nodes, coincident with decreased levels at the mucosal sites, and a decreased ability to elicit an effective anti-SIV antibody response. These data provide evidence that a robust mucosal innate/effector immune response is beneficial following lentiviral exposure; however, it is likely that the anatomical location and timing of the response need to be coordinated to permit an effective immune response able to delay progression to simian AIDS.
The Abundant R2 mRNA Generated by Aleutian Mink Disease Parvovirus Is Tricistronic, Encoding NS2, VP1, and VP2
Authors: Qiu Jianming , Cheng Fang , Pintel David 
Published: April 2007

ABSTRACT

The abundant R2 mRNA encoded by the single left-end promoter of Aleutian mink disease parvovirus is tricistronic; it not only expresses the capsid proteins VP1 and VP2 but is also the major source for the nonstructural protein NS2. A
cis
-acting sequence within the NS2 gene was shown to be required for efficient capsid protein production, and its effect displayed a distinct location dependence. Ribosome transit through the upstream NS2 gene region was necessary for efficient VP1 and VP2 expression; however, neither ablation nor improvement of the NS2 initiating AUG had an effect on capsid protein production, suggesting that the translation of the NS2 protein per se had little influence on VP1 and VP2 expression. Thus, proper control of the alternative translation of the tricistronic R2 mRNA, a process critical for viral replication, is governed in a complex manner.
Pocket Factors Are Unlikely To Play a Major Role in the Life Cycle of Human Rhinovirus
Authors: Katpally Umesh , Smith Thomas J. 
Published: April 2007

ABSTRACT
Human rhinovirus 14 (HRV14) is a member of the rhinovirus genus, which belongs to the picornavirus family, which includes clinically and economically important members, such as poliovirus, foot-and-mouth disease virus, and endomyocarditis virus. Capsid stability plays an important role in the viral infection process, in that it needs to be stable enough to move from cell to cell and yet be able to release its genetic material upon the appropriate environmental cues from the host cell. It has been suggested that certain host cell molecules, “pocket factors,” bind to the WIN drug-binding cavity beneath the canyon floor and provide transient stability to a number of the picornaviruses. To directly test this hypothesis, HRV14 was mutated in (V1188M, C1199W, and V1188M/C1199W) and around (S1223G) the drug-binding pocket. Infectivity, limited proteolysis, and matrix-assisted laser desorption ionization analyses indicate that filling the drug-binding pocket with bulky side chains is not deleterious to the viral life cycle and lends some stabilization to the capsid. In contrast, studies with the S1223G mutant suggest that this mutation at least partially overcomes WIN drug-mediated inhibition of cell attachment and capsid breathing. Finally, HRV16, which is inherently more stable than HRV14 in a number of respects, was found to “breathe” only at 37°C and did not tolerate stabilizing mutations in the drug-binding cavity. These results suggest that it is the drug-binding cavity itself and not the putative pocket factor that is crucial for the capsid dynamics, which is, in turn, necessary for infection.
New Structure Model for the Packaging Signal in the Genome of Group IIa Coronaviruses
Authors: Chen Shih-Cheng , van den Born Erwin , van den Worm Sjoerd H. E. , Pleij Cornelis W. A. , Snijder Eric J. , Olsthoorn René C. L. 
Published: April 2007

ABSTRACT
A 190-nucleotide (nt) packaging signal (PS) located in the 3′ end of open reading frame 1b in the mouse hepatitis virus, a group IIa coronavirus, was previously postulated to direct genome RNA packaging. Based on phylogenetic data and structure probing, we have identified a 95-nt hairpin within the 190-nt PS domain which is conserved in all group IIa coronaviruses but not in the severe acute respiratory syndrome coronavirus (group IIb), group I coronaviruses, or group III coronaviruses. The hairpin is composed of six copies of a repeating structural subunit that consists of 2-nt bulges and 5-bp stems. We propose that repeating AA bulges are characteristic features of group IIa PSs.
Herpes Simplex Virus Type 1 Induces CD83 Degradation in Mature Dendritic Cells with Immediate-Early Kinetics via the Cellular Proteasome
Authors: Kummer Mirko , Turza Nadine M. , Muhl-Zurbes Petra , Lechmann Matthias , Boutell Chris , Coffin Robert S. , Everett Roger D. , Steinkasserer Alexander , Prechtel Alexander T. 
Published: April 2007

ABSTRACTMature dendritic cells (DCs) are the most potent antigen-presenting cells within the human immune system. However, Herpes simplex virus type 1 (HSV-1) is able to interfere with DC biology and to establish latency in infected individuals. In this study, we provide new insights into the mechanism by which HSV-1 disarms DCs by the manipulation of CD83, a functionally important molecule for DC activation. Fluorescence-activated cell sorter (FACS) analyses revealed a rapid downmodulation of CD83 surface expression within 6 to 8 h after HSV-1 infection, in a manner strictly dependent on viral gene expression. Soluble CD83 enzyme-linked immunosorbent assays, together with Western blot analysis, demonstrated that CD83 rapidly disappears from the cell surface after contact with HSV-1 by a mechanism that involves protein degradation rather than shedding of CD83 from the cell surface into the medium. Infection experiments with an ICP0 deletion mutant demonstrated an important role for this viral immediate-early protein during CD83 degradation, since this particular mutant strain leads to strongly reduced CD83 degradation. This hypothesis was further strengthened by cotransfection of plasmids expressing CD83 and ICP0 into 293T cells, which led to significantly reduced accumulation of CD83. In strong contrast, transfection of plasmids expressing CD83 and a mutant ICP0 defective in its RING finger-mediated E3 ubiquitin ligase function did not reduce CD83 expression. Inhibition of the proteasome, the cellular protein degradation machinery, almost completely restored CD83 surface expression during HSV-1 infection, indicating that proteasome-mediated degradation and HSV-1 ICP0 play crucial roles in this novel viral immune escape mechanism.
Construction and Characterization of a Full-Length Infectious Simian T-Cell Lymphotropic Virus Type 3 Molecular Clone
Authors: Chevalier Sébastien Alain , Walic Marine , Calattini Sara , Mallet Adeline , Prévost Marie-Christine , Gessain Antoine , Mahieux Renaud 
Published: April 2007

ABSTRACT

Together with their simian T-cell lymphotropic virus (STLV) equivalent, human T-cell lymphotropic virus type 1 (HTLV-1), HTLV-2, and HTLV-3 form the primate T-cell lymphotropic virus (PTLV) group. Over the years, understanding the biology and pathogenesis of HTLV-1 and HTLV-2 has been widely improved by the creation of molecular clones. In contrast, so far, PTLV-3 experimental studies have been restricted to the overexpression of the
tax
gene using reporter assays. We have therefore decided to construct an STLV-3 molecular clone. We generated a full-length STLV-3 proviral clone (8,891 bp) by PCR amplification of overlapping fragments. This STLV-3 molecular clone was then transfected into 293T cells. Reverse transcriptase PCR experiments followed by sequence analysis of the amplified products allowed us to establish that both
gag
and
tax/rex
mRNAs were transcribed. Western blotting further demonstrated the presence of the STLV-3 p24

gag

protein in the cell culture supernatant from transfected cells. Transient transfection of 293T cells and of 293T-long terminal repeat-green fluorescent protein cells with the STLV-3 clone promoted syncytium formation, a hallmark of PTLV Env expression, as well as the appearance of fluorescent cells, also demonstrating that the Tax3 protein was expressed. Virus particles were visible by electron microscopy. These particles are infectious, as demonstrated by our cell-free-infection experiments with purified virions. All together, our data demonstrate that the STLV-3 molecular clone is functional and infectious. This clone will give us a unique opportunity to study in vitro the different pX transcripts and the putative presence of antisense transcripts and to evaluate the PTLV-3 pathogenicity in vivo.
Genomic and Morphological Features of a Banchine Polydnavirus: Comparison with Bracoviruses and Ichnoviruses
Authors: Lapointe Renée , Tanaka Kohjiro , Barney Walter E. , Whitfield James B. , Banks Jonathan C. , Béliveau Catherine , Stoltz Don , Webb Bruce A. , Cusson Michel 
Published: April 2007

ABSTRACT

Many ichneumonid and braconid endoparasitoids inject a polydnavirus (PDV) into their caterpillar hosts during oviposition. The viral entities carried by wasps of these families are referred to as “ichnoviruses” (IVs) and “bracoviruses” (BVs), respectively. All IV genomes characterized to date are found in wasps of the subfamily Campopleginae; consequently, little is known about PDVs found in wasps of the subfamily Banchinae, the only other ichneumonid taxon thus far shown to carry these viruses. Here we report on the genome sequence and virion morphology of a PDV carried by the banchine parasitoid
Glypta fumiferanae
. With an aggregate genome size of ∼290 kb and 105 genome segments, this virus displays a degree of genome segmentation far greater than that reported for BVs or IVs. The size range of its genome segments is also lower than those in the latter two groups. As reported for other PDVs, the predicted open reading frames of this virus cluster into gene families, including the protein tyrosine phosphatase (PTP) and viral ankyrin (
ank
) families, but phylogenetic analysis indicates that
ank
genes of the
G. fumiferanae
virus are not embedded within the IV lineage, while its PTPs and those of BVs form distinct clusters. The banchine PDV genome also encodes a novel family of NTPase-like proteins displaying a pox-D5 domain. The unique genomic features of the first banchine virus examined, along with the morphological singularities of its virions (IV-like nucleocapsids, but enveloped in groups like some of the BVs), suggest that they could have an origin distinct from those of IVs and BVs.