bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of a Potential Paracrine Angiogenic Loop between Human THP-1 Macrophages and Human Microvascular Endothelial Cells duringBartonella henselaeInfection
Authors: Resto-Ruiz Sandra I. , Schmiederer Michael , Sweger Debra , Newton Catherine , Klein Thomas W. , Friedman Herman , Anderson Burt E. 
Published: July 2002

ABSTRACTBartonella henselaeis responsible for various disease syndromes that loosely correlate with the immune status of the host. In the immunocompromised individual,B. henselae-induced angiogenesis, or bacillary angiomatosis, is characterized by vascular proliferative lesions similar to those in Kaposi's sarcoma. We hypothesize thatB. henselae-mediated interaction with immune cells, namely, macrophages, induces potential angiogenic growth factors and cytokines which contribute in a paracrine manner to the proliferation of endothelial cells. Vascular endothelial growth factor (VEGF), a direct inducer of angiogenesis, and interleukin-1β (IL-1β), a potentiator of VEGF, were detected within 12 and 6 h, respectively, in supernatants from phorbol 12-myristate 13-acetate-differentiated human THP-1 macrophages exposed to liveB. henselae.Pretreatment of macrophages with cytochalasin D, a phagocytosis inhibitor, yielded comparable results, suggesting that bacterium-cell attachment is sufficient for VEGF and IL-1β induction. IL-8, an angiogenic cytokine with chemotactic properties, was induced in human microvascular endothelial cells (HMEC-1) within 6 h of infection, whereas no IL-8 induction was observed in infected THP-1 cells. In addition, conditioned medium from infected macrophages induced the proliferation of HMEC-1, thus demonstrating angiogenic potential. These data suggest thatBartonellamodulation of host or target cell cytokines and growth factors, rather than a direct role of the bacterium as an endothelial cell mitogen, is the predominant mechanism responsible for angiogenesis.B. henselaeinduction of VEGF, IL-1β, and IL-8 outlines a broader potential paracrine angiogenic loop whereby macrophages play the predominant role as the effector cell and endothelial cells are the final target cell, resulting in their proliferation.
High Expression of a C Protein β Antigen Gene among Invasive Strains from Certain Clonally Related Groups of Type Ia and Ib Group B Streptococci
Authors: Nagano Noriyuki , Nagano Yukiko , Taguchi Fumiaki 
Published: July 2002

ABSTRACT
Serotyped strains of group B streptococci can be divided into subtypes based on restriction endonuclease digestion patterns (RDP). Profiles of cell-bound proteins were compared among RDP types. Proteins that showed a remarkable difference in the degree of expression were found among strains of RDP Ia-3, which has been considered potentially virulent, as well as of RDP Ib-1. For RDP Ia-3 strains, the protein was predominant in strains from cerebrospinal fluid (CSF) but was mostly a minor component in other strains. For RDP Ib-1 strains, the protein was predominant in strains from CSF, showed diversity in strains from blood, and was mostly a minor component in other strains. By N-terminal sequencing analysis, the protein was identified as a C protein β antigen. The level of bound immunoglobulin A (IgA) or anti-β antigen monoclonal antibody correlated with the level of expressed β antigen, and invasive strains showed remarkably high levels of binding; the exception was a CSF-derived strain of RDP Ib-1 which produced a large amount of β antigen and showed a high level of binding of anti-β antigen monoclonal antibody but no IgA binding. PCR-based amplification revealed that the β antigen gene was detected in all RDP Ia-3 and Ib-1 strains but was not found in any strains of other RDP types. Competitive reverse transcriptase PCR demonstrated that the difference in the amount of protein produced was due to the difference in the level of expression of the β antigen mRNA. Our findings imply that differences in gene expression for a protein may contribute to the invasiveness of RDP Ia-3 and Ib-1 strains for the host.
DNA Polymerases of Low-GC Gram-Positive Eubacteria: Identification of the Replication-Specific Enzyme Encoded by
dnaE
Authors: Barnes Marjorie H. , Miller Shelley D. , Brown Neal C. 
Published: July 2002

ABSTRACT

dna
E, the gene encoding one of the two replication-specific DNA polymerases (Pols) of low-GC-content gram-positive bacteria (E. Dervyn et al., Science 294:1716-1719, 2001; R. Inoue et al., Mol. Genet. Genomics 266:564-571, 2001), was cloned from
Bacillus subtilis
, a model low-GC gram-positive organism. The gene was overexpressed in
Escherichia coli
. The purified recombinant product displayed inhibitor responses and physical, catalytic, and antigenic properties indistinguishable from those of the low-GC gram-positive-organism-specific enzyme previously named DNA Pol II after the
polB
-encoded DNA Pol II of
E. coli
. Whereas a
polB
-like gene is absent from low-GC gram-positive genomes and whereas the low-GC gram-positive DNA Pol II strongly conserves a
dnaE
-like, Pol III primary structure, it is proposed that it be renamed DNA polymerase III E (Pol III E) to accurately reflect its replicative function and its origin from
dnaE
. It is also proposed that DNA Pol III, the other replication-specific Pol of low-GC gram-positive organisms, be renamed DNA polymerase III C (Pol III C) to denote its origin from
polC
. By this revised nomenclature, the DNA Pols that are expressed constitutively in low-GC gram-positive bacteria would include DNA Pol I, the dispensable repair enzyme encoded by
polA
, and the two essential, replication-specific enzymes Pol III C and Pol III E, encoded, respectively, by
polC
and
dnaE
.
Cleavage of
Treponema denticola
PrcA Polypeptide To Yield Protease Complex-Associated Proteins Prca1 and Prca2 Is Dependent on PrtP
Authors: Lee Si Young , Bian Xue-Lin , Wong Grace W. K. , Hannam Pauline M. , McBride Barry C. , Fenno J. Christopher 
Published: July 2002

ABSTRACT

Analysis of potential virulence factors of oral spirochetes focuses on surface and secreted proteins. The
Treponema denticola
chymotrypsin-like protease (CTLP) is implicated in degradation of host cell molecules and contributes to tissue invasion. The CTLP complex, composed of the 72-kDa PrtP protein and two auxiliary proteins with molecular masses of approximately 40 and 30 kDa, is also involved in localization and oligomerization of the
T. denticola
major surface protein (Msp). The larger auxiliary protein was reported to be encoded by an open reading frame (ORF2) directly upstream of
prtP
. The deduced 39-kDa translation product of ORF2 contains a sequence matching the N-terminal sequence determined from one of the CTLP complex proteins. No proteins with significant homology are known, nor was information available on the third protein of the complex. DNA sequence analysis showed that ORF2 extended an additional 852 bp upstream of the reported sequence. The complete gene, designated
prcA
, encodes a predicted N-terminally-acylated polypeptide of approximately 70 kDa. Isogenic mutants with mutations in
prtP
,
prcA
, and
prcA-prtP
all lacked CTLP protease activity. The
prcA
mutant lacked all three CTLP proteins. The
prcA
-
prtP
mutant produced only a C-terminally-truncated 62-kDa PrcA protein. The
prtP
mutant produced a full-length 70-kDa PrcA. Immunoblot analysis of recombinant PrcA constructs confirmed that PrcA is cleaved to yield the two smaller proteins of the CTLP complex, designated PrcA1 and PrcA2. These data indicate that PrtP is required for cleavage of PrcA and suggest that this cleavage may be required for formation or stability of outer membrane complexes.
Aquaporin Z of
Escherichia coli
: Reassessment of Its Regulation and Physiological Role
Authors: Soupene Eric , King Natalie , Lee Haidy , Kustu Sydney 
Published: July 2002

ABSTRACT

Transcription of an
aqpZ-lac
fusion in a single copy on the
Escherichia coli
chromosome increased as cells entered the stationary growth phase. This was true in a variety of media, and increased transcription in enriched medium required the RpoS sigma factor. Expression of the
aqpZ
-
lac
fusion was not affected by up- or downshifts in osmolality. Disruption of
aqpZ
had no detectable adverse effects.
Highly Sensitive Multiplex Assay for Detection of Human Immunodeficiency Virus Type 1 and Hepatitis C Virus RNA
Authors: Giachetti C. , Linnen J. M. , Kolk D. P. , Dockter J. , Gillotte-Taylor K. , Park M. , Ho-Sing-Loy M. , McCormick M. K. , Mimms L. T. , McDonough S. H. 
Published: July 2002

ABSTRACT
Various nucleic acid assays have been developed and implemented for diagnostics and therapeutic monitoring of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infections. The high-throughput, semiautomated assays described here were developed to provide a method suitable for screening plasma specimens for the presence of HIV-1 and HCV RNAs. Three assays were developed: a multiplex HIV-1/HCV assay for simultaneous detection of HIV-1 and HCV, and discriminatory assays for specific detection of HIV-1 and HCV. The assay systems utilize three proprietary technologies: (i) target capture-based sample preparation, (ii) transcription-mediated amplification (TMA), and (iii) hybridization protection assay (HPA). An internal control is incorporated into each reaction to control for every step of the assay and identify random false-negative reactions. The assays demonstrated a sensitivity of at least 100 copies/ml for each target, and they detected with similar sensitivity all major variants of HCV and HIV-1, including HIV-1 group O strains. Assay sensitivity for one virus was not affected by the presence of the other. The specificity of these TMA-driven assays was ≥99.5% in both normal donor specimens and plasma containing potentially interfering substances or other blood-borne pathogens. Statistical receiver operating characteristic plots of 1 − specificity versus sensitivity data determined very wide analyte cutoff values for each assay at the point at which the assay specificity and sensitivity were both ≥99.5%. The sensitivity, specificity, and throughput capability predict that these assays will be valuable for large-volume plasma screening, either in a blood bank setting or in other diagnostic applications.
Evaluation of 15 Motility Media and a Direct Microscopic Method for Detection of Motility in Enterococci
Authors: Van Horn Kenneth , Tóth Clara , Kariyama Reiko , Mitsuhata Ritsuko , Kumon Hiromi 
Published: July 2002

ABSTRACT

Isolation of motile,
vanC
enterococci has yet to be a major infection control concern; however, rapid detection still is important. We evaluated 15 motility media from three manufacturers and a 2-h direct microscopic method for accurate detection of 89 enterococcal strains, including 72
vanC
enterococcal strains. Resistance genes were confirmed by a multiplex PCR method with the
vanC
gene detected in all motile enterococci. Motility in the 72
vanC
enterococci was detected at 30°C within 72 h in BD Biosciences motility nitrate medium and in Remel motility B medium, motility B medium supplemented with methyl-α-
d
-glucopyranoside (investigational), motility S medium, motility test medium, and motility test medium with tetrazolium indicator. Motility was also observed for all
vanC
enterococci with the 2-h direct (30°C incubation) microscopic detection method. All
Enterococcus faecalis
and
Enterococcus faecium
isolates were observed to be nonmotile in all media and by the direct microscopic method. Since differences between the various motility media tested were observed, the medium used for detection of enterococcal motility must be selected carefully.
Performance of CHROMagar Selective Medium and Oxacillin Resistance Screening Agar Base for Identifying
Staphylococcus aureus
and Detecting Methicillin Resistance
Authors: Kluytmans Jan , Van Griethuysen Arjanne , Willemse Piet , Van Keulen Peter 
Published: July 2002

ABSTRACT

Two new selective media, oxacillin resistance screening agar base (ORSAB) and CHROMagar Staph aureus (CSA), were evaluated for identification of
Staphylococcus aureus
and for screening of methicillin resistance by addition of antimicrobial agents to these media. A well-defined collection consisting of 1,140 staphylococci was used. A total of 624 were
S. aureus
, of which 358 were methicillin susceptible and 266 were methicillin resistant, and 516 were coagulase-negative staphylococci. The methicillin-resistant
S. aureus
(MRSA) strains were selected based on the results of phage typing; 247 different types were included in the analysis. For identification of
S. aureus
, both media performed better after 24 h than after 48 h. The sensitivities at 24 h were comparable (CSA, 98.6%; ORSAB, 97.1%), but the specificity of CSA was significantly higher (CSA, 97.1%; ORSAB, 92.1%). For screening of methicillin resistance, antibiotic supplements were added to both media. The sensitivity was lower after 24 h (CSA, 58.6%; ORSAB, 84.2%) and increased significantly after 48 h (CSA, 77.5%; ORSAB, 91.4%). At both time intervals ORSAB was significantly more sensitive than CSA. However, the specificities of both media were high after 24 h (CSA, 99.1%; ORSAB, 98.3%) and decreased significantly after 48 h of incubation (CSA, 94.7%; ORSAB, 95.5%). In conclusion, for identification of
S. aureus
, CSA is more accurate than ORSAB because of a significantly higher specificity. For screening of MRSA, ORSAB performs better than CSA, but the usefulness in clinical practice is limited because a significant number of strains are not detected.
Phenotypic and Genotypic Characterization of Serologically Atypical Strains ofShigella flexneriType 4 Isolated in Dhaka, Bangladesh
Authors: Talukder Kaisar A. , Islam M. Aminul , Dutta Dilip K. , Hassan Ferdaus , Safa Ashrafus , Nair G. B. , Sack David A. 
Published: July 2002

ABSTRACTTwenty-one atypicalShigella flexneritype 4 strains isolated from patients attending the Dhaka treatment center of the International Centre for Diarrhoeal Disease Research, Bangladesh, were extensively characterized and compared withS. flexneriserotypes 4a and 4b. The atypical strains agglutinated only with the type antigen factor 4 and did not agglutinate with any group factors, thereby excluding their characterization into serotype 4a or 4b. Of the 21 strains, 85.7% did not ferment mannitol but were able to ferment most of the sugars, whereas the remaining 14.3% strains fermented mannitol but were unable to ferment most of the sugars. Most of the strains were resistant to ampicillin, tetracycline, and trimethoprim-sulfomethoxazole. All of the strains harbored the 140-MDa plasmid, had theipaHgene, had thesengene (encodingShigellaenterotoxin 2), had the ability to bind Congo red, and were positive for keratoconjunctivitis in the guinea pig eye, attesting their invasive properties. All of the strains contained a middle-range plasmid (35 to 62 MDa) as well as a number of stable small plasmids, yielding mainly two plasmid profiles which were different from those of 4a and 4b strains. Conjugation and curing experiments suggested that the middle-range plasmids harbored a self-transferable multiple antibiotic resistance marker. Pulsed-field gel electrophoresis analysis of all of the tested strains yielded two types with numerous subtypes, whereas ribotyping yielded only two types which were completely different from those of types 4a and 4b. This study concluded that two different clones of atypicalS. flexneritype 4 exist and strongly suggests that these are new subserotypes ofS. flexnerithat await further serological classification.
Prevalence of Enterotoxigenic
Escherichia coli
Strains Harboring the Longus Pilus Gene in Brazil
Authors: Nishimura Lucilia S. , Girón Jorge A. , Nunes Solange L. , Guth Beatriz E. C. 
Published: July 2002

ABSTRACT

The longus type IV pilus gene (
lngA
) was highly prevalent (32.8%) among Brazilian enterotoxigenic
Escherichia coli
strains producing both heat-labile and heat-stable enterotoxins and bearing the CFA/I, CS1CS3, or CS6 antigen. Furthermore,
lngA
was more often found in strains isolated from children with diarrhea than in strains isolated from children without diarrhea.
Quantitative Stability of DNA after Extended Storage of Clinical Specimens as Determined by Real-Time PCR
Authors: Jerome Keith R. , Huang Meei-Li , Wald Anna , Selke Stacy , Corey Lawrence 
Published: July 2002

ABSTRACT
Viral DNA stored for extended periods can be amplified by PCR. However, it is unknown whether stored specimens give accurate quantitative results by newer real-time PCR techniques. We therefore compared herpes simplex virus DNA levels in specimens before and after 16 months of storage. The levels of viral DNA remained stable whether the DNA was stored as purified DNA or unextracted DNA in a whole specimen.
Molecular and Seroepidemiological Evidence of Canine Calicivirus Infections in Japan
Authors: Mochizuki Masami , Hashimoto Michiru , Roerink Frank , Tohya Yukinobu , Matsuura Yuichi , Sasaki Nobuo 
Published: July 2002

ABSTRACT
Calicivirus infection of dogs was epidemiologically investigated by using canine calicivirus (CaCV) strain 48 as a reference. Similar RNA polymerase gene sequences and neutralizing antibodies against CaCV were detected in 1.7% of clinical specimens and 57% of serum samples, respectively, suggesting a high prevalence of CaCV in dog populations.
Prevalence of the
fsr
Locus in
Enterococcus faecalis
Infections
Authors: Pillai S. K. , Sakoulas G. , Gold H. S. , Wennersten C. , Eliopoulos G. M. , Moellering R. C. , Inouye R. T. 
Published: July 2002

ABSTRACT

The
fsr
locus of
Enterococcus faecalis
confers virulence in animal models. A retrospective analysis of
fsr
prevalence in diverse
E. faecalis
clinical isolates demonstrated
fsr
in all endocarditis isolates versus 53% of stool isolates (
P
= 0.005). This supports a role for
fsr
-mediated virulence in the pathogenesis of enterococcal infections in humans.
Application of RNA Polymerase β-Subunit Gene (
rpoB
) Sequences for the Molecular Differentiation of
Legionella
Species
Authors: Ko Kwan Soo , Lee Hae Kyung , Park Mi-Yeoun , Lee Keun-Hwa , Yun Yeo-Jun , Woo So-Yon , Miyamoto Hiroshi , Kook Yoon-Hoh 
Published: July 2002

ABSTRACT

The nucleotide sequences of the partial
rpoB
gene were determined from 38
Legionella
species, including 15 serogroups of
Legionella pneumophila.
These sequences were then used to infer the phylogenetic relationships among the
Legionella
species in order to establish a molecular differentiation method appropriate for them. The sequences (300 bp) and the phylogenetic tree of
rpoB
were compared to those from analyses using 16S rRNA gene and
mip
sequences. The trees inferred from these three gene sequences revealed significant differences. This sequence incongruence between the
rpoB
tree and the other trees might have originated from the high frequency of synonymous base substitutions and/or from horizontal gene transfer among the
Legionella
species. The nucleotide variation of
rpoB
enabled more evident differentiation among the
Legionella
species than was achievable by the 16S rRNA gene and even by
mip
in some cases. Two subspecies of
L. pneumophila
(
L. pneumophila
subsp.
pneumophila
and subsp.
fraseri
) were clearly distinguished by
rpoB
but not by 16S rRNA gene and
mip
analysis. One hundred and five strains isolated from patient tissues and environments in Korea and Japan could be identified by comparison of
rpoB
sequence similarity and phylogenetic trees. These results suggest that the partial sequences of
rpoB
determined in this study might be applicable to the molecular differentiation of
Legionella
species.
Bacteremia Due to
Moraxella atlantae
in a Cancer Patient
Authors: De Baere Thierry , Muylaert An , Everaert Els , Wauters Georges , Claeys Geert , Verschraegen Gerda , Vaneechoutte Mario 
Published: July 2002

ABSTRACT

A gram-negative alkaline phosphatase- and pyrrolidone peptidase-positive rod-shaped bacterium (CCUG 45702) was isolated from two aerobic blood cultures from a female cancer patient. No identification could be reached using phenotypic techniques. Amplification of the tRNA intergenic spacers revealed fragments with lengths of 116, 133, and 270 bp, but no such pattern was present in our reference library. Sequencing of the 16S rRNA gene revealed its identity as
Moraxella atlantae
, a species isolated only rarely and published only once as causing infection. In retrospect, the phenotypic characteristics fit the identification as
M. atlantae
(formerly known as CDC group M-3). Comparative 16S rRNA sequence analysis indicates that
M. atlantae
,
M. lincolnii
, and
M. osloensis
might constitute three separate genera within the
Moraxellaceae
. After treatment with amoxicillin-clavulanic acid for 2 days, fever subsided and the patient was dismissed.
Selection of 3′-Template Bases and Initiating Nucleotides by Hepatitis C Virus NS5B RNA-Dependent RNA Polymerase
Authors: Shim Jae Hoon , Larson Gary , Wu Jim Zhen , Hong Zhi 
Published: July 2002

ABSTRACT
De novo RNA synthesis by hepatitis C virus (HCV) nonstructural protein 5B (NS5B) RNA-dependent RNA polymerase has been investigated using short RNA templates. Various templates including those derived from the HCV genome were evaluated by examining the early steps of de novo RNA synthesis. NS5B was shown to be able to produce an initiation dinucleotide product from templates as short as 4-mer and from the 3′-terminal sequences of both plus and minus strands of the HCV RNA genome. GMP, GDP, and guanosine were able to act as an initiating nucleotide in de novo RNA synthesis, indicating that the triphosphate moiety is not absolutely required by an initiating nucleotide. Significant amounts of the initiation product accumulated in de novo synthesis, and elongation from the dinucleotide was observed when large amounts of dinucleotide were available. This result suggests that NS5B, a template, and incoming nucleotides are able to form an initiation complex that aborts frequently by releasing the dinucleotide product before transition to an elongation complex. The transition is rate limiting. Furthermore, we discovered that the secondary structure of a template was not essential for de novo initiation and that 3′-terminal bases of a template conferred specificity in selection of an initiation site. Initiation can occur at the +1, +2, or +3 position numbered from the 3′ end of a template depending on base composition. Pyrimidine bases at any of the three positions are able to serve as an initiation site, while purine bases at the +2 and +3 positions do not support initiation. This result implies that HCV possesses an intrinsic ability to ensure that de novo synthesis is initiated from the +1 position and to maintain the integrity of the 3′ end of its genome. This assay system should be an important tool for investigating the detailed mechanism of de novo initiation by HCV NS5B as well as other viral RNA polymerases.