bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrapulmonary Pharmacokinetics of Telithromycin, a New Ketolide, in Healthy Japanese Volunteers
Authors: Kadota Jun-Ichi , Ishimatsu Yuji , Iwashita Tetsuji , Matsubara Yuichi , Tomono Kazunori , Tateno Masao , Ishihara Roza , Muller-Serieys Claudette , Kohno Shigeru 
Published: July 2002

ABSTRACT
The concentrations of telithromycin, a new ketolide antimicrobial agent, in alveolar macrophages (AMs) and bronchoalveolar epithelial lining fluid (ELF) were determined in order to investigate the transfer of the drug into target tissue, relative to plasma, following multiple oral doses of telithromycin. Twenty-four healthy male Japanese volunteers were randomly allocated to four groups. Each subject was given 600 or 800 mg of telithromycin once daily for 5 days, followed by bronchoalveolar lavage (BAL) 2 or 8 h after the last dose (group A and B: 600 mg, 2 and 8 h BAL time point; group C and D: 800 mg, 2 and 8 h BAL time point). The mean concentrations of the drug in AMs and ELF were 34.54 and 4.92 mg/liter in group A, 50.97 and 2.26 mg/liter in group B, 25.47 and 4.24 mg/liter in group C, and 108.22 and 4.31 mg/liter in group D, respectively, which markedly exceeded concentrations in plasma. These results demonstrated good transfer of telithromycin into AMs and ELF, suggesting good efficacy against common respiratory pathogens, including intracellular pathogens and atypical microorganisms.
Enantiomeric Degradation of 2-(4-Sulfophenyl)Butyrate via 4-Sulfocatechol inDelftia acidovoransSPB1
Authors: Schulz Saskia , Dong Wenbo , Groth Ulrich , Cook Alasdair M. 
Published: July 2002

ABSTRACTEnrichment cultures with enantiomeric 2-(4-sulfophenyl)butyrate (SPB) as the sole added source(s) of carbon and energy for growth yielded a pure culture of a degradative bacterium, which was identified asDelftia acidovoransSPB1. The organism utilized the enantiomers sequentially.R-SPB was utilized first (specific growth rate [μ] = 0.28 h−1), with transient excretion of an unknown intermediate, which was identified as 4-sulfocatechol (4SC). Utilization ofS-SPB was slower (μ = 0.016 h−1) and was initiated only after the first enantiomer was exhausted. Suspensions of cells grown inS-SPB excreted 4SC, so metabolism of the two enantiomers converged at 4SC. The latter was degraded byorthocleavage via 3-sulfo-cis,cis-muconate. Strain SPB1 grew with 4SC and with 1-(4-sulfophenyl)octane (referred to herein as model LAS) but not with commercial linear alkylbenzenesulfonate (LAS) surfactant, which is subterminally substituted but nontoxic. It would appear that metabolism of the model LAS does not represent metabolism of commercial LAS.
Evaluation of Immunomagnetic Separation for Recovery of
Cryptosporidium parvum
and
Giardia duodenalis
from High-Iron Matrices
Authors: Yakub Gary P. , Stadterman-Knauer Kathleen L. 
Published: July 2002

ABSTRACT

In this study we examined the recovery of
Cryptosporidium parvum
and
Giardia duodenalis
from matrices containing various concentrations of dissolved iron. The organisms were recovered by using the immunomagnetic separation-immunofluorescent assay method, and the levels of recovery were compared to the dissolved iron concentrations. The levels of recovery of
C. parvum
decreased sharply at dissolved iron concentrations greater than 4 mg/liter, while the levels of recovery of
G. duodenalis
decreased sharply at concentrations greater than 40 mg/liter.
A Large Gene Cluster Encoding Several Magnetosome Proteins Is Conserved in Different Species of Magnetotactic Bacteria
Authors: Grünberg Karen , Wawer Cathrin , Tebo Bradley M. , Schüler Dirk 
Published: July 2002

ABSTRACT

In magnetotactic bacteria, a number of specific proteins are associated with the magnetosome membrane (MM) and may have a crucial role in magnetite biomineralization. We have cloned and sequenced the genes of several of these polypeptides in the magnetotactic bacterium
Magnetospirillum gryphiswaldense
that could be assigned to two different genomic regions. Except for
mamA
, none of these genes have been previously reported to be related to magnetosome formation. Homologous genes were found in the genome sequences of
M. magnetotacticum
and magnetic coccus strain MC-1. The MM proteins identified display homology to tetratricopeptide repeat proteins (MamA), cation diffusion facilitators (MamB), and HtrA-like serine proteases (MamE) or bear no similarity to known proteins (MamC and MamD). A major gene cluster containing several magnetosome genes (including
mamA
and
mamB
) was found to be conserved in all three of the strains investigated. The
mamAB
cluster also contains additional genes that have no known homologs in any nonmagnetic organism, suggesting a specific role in magnetosome formation.
Experimental and Field Studies ofEscherichia coliO157:H7 in White-Tailed Deer
Authors: Fischer John R. , Zhao Tong , Doyle Michael P. , Goldberg Martin R. , Brown Cathy A. , Sewell Christopher T. , Kavanaugh Darrell M. , Bauman Christopher D. 
Published: July 2002

ABSTRACTStudies were conducted to evaluate fecal shedding ofEscherichia coliO157:H7 in a small group of inoculated deer, determine the prevalence of the bacterium in free-ranging white-tailed deer, and elucidate relationships betweenE. coliO157:H7 in wild deer and domestic cattle at the same site. Six young, white-tailed deer were orally administered 108CFU ofE. coliO157:H7. Inoculated deer were sheddingE. coliO157:H7 by 1 day postinoculation (DPI) and continued to shed decreasing numbers of the bacteria throughout the 26-day trial. Horizontal transmission to an uninoculated deer was demonstrated. AlthoughE. coliO157:H7 bacteria were recovered from the gastrointestinal tracts of deer necropsied from 4 to 26 DPI, attaching and effacing lesions were not apparent in any deer. Results are similar to those of inoculation studies in calves and sheep. In field studies,E. coliO157 was not detected in 310 fresh deer fecal samples collected from the ground. It was detected in feces, but not in meat, from 3 of 469 free-ranging deer in 1997. In 1998,E. coliO157 was not detected in 140 deer at the single positive site found in 1997; however, it was recovered from 13 of 305 dairy and beef cattle at the same location. Isolates ofE. coliO157:H7 from deer and cattle at this site differed with respect to pulsed-field gel electrophoresis patterns and genes encoding Shiga toxins. The low overall prevalence ofE. coliO157:H7 and the identification of only one site with positive deer suggest that wild deer are not a major reservoir ofE. coliO157:H7 in the southeastern United States. However, there may be individual locations where deer sporadically harbor the bacterium, and venison should be handled with the same precautions recommended for beef, pork, and poultry.
Export of Cytochrome P450 105D1 to the Periplasmic Space of
Escherichia coli
Authors: Kaderbhai Mustak A. , Ugochukwu Cynthia C. , Kelly Steven L. , Lamb David C. 
Published: July 2002

ABSTRACT

CYP105D1, a cytochrome P450 from
Streptomyces griseus,
was appended at its amino terminus to the secretory signal of
Escherichia coli
alkaline phosphatase and placed under the transcriptional control of the native
phoA
promoter. Heterologous expression in
E. coli
phosphate-limited medium resulted in abundant synthesis of recombinant CYP105D1 that was translocated across the bacterial inner membrane and processed to yield authentic, heme-incorporated P450 within the periplasmic space. Cell extract and whole-cell activity studies showed that the periplasmically located CYP105D1 competently catalyzed NADH-dependent oxidation of the xenobiotic compounds benzo[
a
]pyrene and erythromycin, further revealing the presence in the
E. coli
periplasm of endogenous functional redox partners. This system offers substantial advantages for the application of P450 enzymes to whole-cell biotransformation strategies, where the ability of cells to take up substrates or discard products may be limited.
Adhesion of
Pseudomonas fluorescens
(ATCC 17552) to Nonpolarized and Polarized Thin Films of Gold
Authors: Busalmen J. P. , de Sánchez S. R. 
Published: July 2002

ABSTRACT

The adhesion of
Pseudomonas fluorescens
(ATCC 17552) to nonpolarized and negatively polarized thin films of gold was studied in situ by contrast microscopy using a thin-film electrochemical flow cell. The influence of the electrochemical potential was evaluated at two different ionic strengths (0.01 and 0.1 M NaCl; pH 7) under controlled flow. Adhesion to nonpolarized gold surfaces readily increased with the time of exposition at both ionic-strength values. At negative potentials (−0.2 and −0.5 V [Ag/AgCl-KCl saturated {sat.}]), on the other hand, bacterial adhesion was strongly inhibited. At 0.01 M NaCl, the inhibition was almost total at both negative potentials, whereas at 0.1 M NaCl the inhibition was proportional to the magnitude of the potential, being almost total at −0.5 V. The existence of reversible adhesion was investigated by carrying out experiments under stagnant conditions. Reversible adhesion was observed only at potential values very close to the potential of zero charge of the gold surface (0.0 V [Ag/AgCl-KCl sat.]) at a high ionic strength (0.1 M NaCl). Theoretical calculations of the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy for the bacteria-gold interaction were in good agreement with experimental results at low ionic strength (0.01 M). At high ionic strength (0.1 M), deviations from DLVO behavior related to the participation of specific interactions were observed, when surfaces were polarized to negative potentials.
Specific Detection of
Bradyrhizobium
and
Rhizobium
Strains Colonizing Rice (
Oryza sativa
) Roots by 16S-23S Ribosomal DNA Intergenic Spacer-Targeted PCR
Authors: Tan Zhiyuan , Hurek Thomas , Vinuesa Pablo , Müller Peter , Ladha Jagdish K. , Reinhold-Hurek Barbara 
Published: July 2002

ABSTRACT

In addition to forming symbiotic nodules on legumes, rhizobial strains are members of soil or rhizosphere communities or occur as endophytes, e.g., in rice. Two rhizobial strains which have been isolated from root nodules of the aquatic legumes
Aeschynomene fluminensis
(IRBG271) and
Sesbania aculeata
(IRBG74) were previously found to promote rice growth. In addition to analyzing their phylogenetic positions, we assessed the suitability of the 16S-23S ribosomal DNA (rDNA) intergenic spacer (IGS) sequences for the differentiation of closely related rhizobial taxa and for the development of PCR protocols allowing the specific detection of strains in the environment. 16S rDNA sequence analysis (sequence identity, 99%) and phylogenetic analysis of IGS sequences showed that strain IRBG271 was related to but distinct from
Bradyrhizobium elkanii
.
Rhizobium
sp. (
Sesbania
) strain IRBG74 was located in the
Rhizobium
-
Agrobacterium
cluster as a novel lineage according to phylogenetic 16S rDNA analysis (96.8 to 98.9% sequence identity with
Agrobacterium tumefaciens;
emended name,
Rhizobium radiobacter
). Strain IRBG74 harbored four copies of rRNA operons whose IGS sequences varied only slightly (2 to 9 nucleotides). The IGS sequence analyses allowed intraspecies differentiation, especially in the genus
Bradyrhizobium,
as illustrated here for strains of
Bradyrhizobium japonicum, B. elkanii, Bradyrhizobium liaoningense,
and
Bradyrhizobium
sp. (
Chamaecytisus
) strain BTA-1. It also clearly differentiated fast-growing rhizobial species and strains, albeit with lower statistical significance. Moreover, the high sequence variability allowed the development of highly specific IGS-targeted nested-PCR assays. Strains IRBG74 and IRBG271 were specifically detected in complex DNA mixtures of numerous related bacteria and in the DNA of roots of gnotobiotically cultured or even of soil-grown rice plants after inoculation. Thus, IGS sequence analysis is an attractive technique for both microbial ecology and systematics.
Characterization of Cyt2Bc Toxin from
Bacillus thuringiensis
subsp.
medellin
Authors: Juárez-Pérez Victor , Guerchicoff Alejandra , Rubinstein Clara , Delécluse Armelle 
Published: July 2002

ABSTRACT

We cloned and sequenced a new cytolysin gene from
Bacillus thuringiensis
subsp.
medellin
. Three IS
240
-like insertion sequence elements and the previously cloned
cyt1Ab
and
p21
genes were found in the vicinity of the cytolysin gene. The cytolysin gene encodes a protein 29.7 kDa in size that is 91.5% identical to Cyt2Ba from
Bacillus thuringiensis
subsp.
israelensis
and has been designated Cyt2Bc. Inclusions containing Cyt2Bc were purified from the crystal-negative strain SPL407 of
B. thuringiensis
. Cyt2Bc reacted weakly with antibodies directed against Cyt2Ba and was not recognized by an antiserum directed against the reference cytolysin Cyt1Aa. Cyt2Bc was hemolytic only upon activation with trypsin and had only one-third to one-fifth of the activity of Cyt2Ba, depending on the activation time. Cyt2Bc was also mosquitocidal against
Aedes aegypti
,
Anopheles stephensi
, and
Culex quinquefasciatus
, including strains resistant to the
Bacillus sphaericus
binary toxin. Its toxicity was half of that of Cyt2Ba on all mosquito species except resistant
C. quinquefasciatus
.
Immunoglobulin A (IgA) Deficiency and Alternative Celiac Disease-Associated Antibodies in Sera Submitted to a Reference Laboratory for Endomysial IgA Testing
Authors: Prince Harry E. , Norman Gary L. , Binder Walter L. 
Published: July 2002

ABSTRACTImmunoglobulin A (IgA) deficiency occurs more frequently in patients with celiac disease (CD) than in the general population and can lead to false-negative results in the best serologic test for CD, endomysial IgA (EMA). To evaluate the impact of IgA deficiency on serologic detection of CD in a reference laboratory setting, IgA levels were measured in 510 consecutive serum specimens submitted for testing for EMA; 510 consecutive serum specimens submitted forHelicobacter pyloriIgG testing served as a gastrointestinal symptom control group. The frequency of IgA deficiency was significantly higher among the specimens submitted for testing for EMA (5.1%) than among the specimens from the symptom control group (1.4%). Three subsets of sera from the group of specimens submitted for testing for EMA were then tested by additional serologic assays for CD; these subsets were EMA-positive sera (n= 25), EMA-negative, IgA-deficient sera (n= 26), and control sera (from EMA-negative, IgA-nondeficient patients age matched to IgA-deficient patients;n= 26). The proportions of EMA-positive sera positive by other assays for CD were 92% for transglutaminase IgA (TG-IgA), 80% for gliadin IgA, 84% for gliadin IgG, 60% for endomysial IgG (EMG), and 32% for transglutaminase IgG (TG-IgG). Very low proportions (0 to 8%) of IgA-deficient sera and control sera were positive for TG-IgA, gliadin IgA, EMG, and TG-IgG. Eight of 26 (31%) IgA-deficient serum samples were positive for gliadin IgG, whereas 3 of 26 (12%) control serum samples were positive for gliadin IgG, but this difference was not statistically significant. Physicians supplied clinical data for 18 of 26 patients with IgA deficiency; only 4 patients had undergone small-bowel biopsy, and 0 of 4 patients showed villous atrophy. These findings show that IgA deficiency is found more frequently among sera submitted for testing for EMA in a reference laboratory setting, but there was no clear-cut serologic or clinical evidence of CD in EMA-negative, IgA-deficient patients.
Prevalence of CagA and VacA Antibodies in Children with
Helicobacter pylori
-Associated Peptic Ulcer Compared to Prevalence in Pediatric Patients with Active or Nonactive Chronic Gastritis
Authors: Alarcón T. , Martínez M. J. , Urruzuno P. , Cilleruelo M. L. , Madruga D. , Sebastian M. , Domingo D. , Sanz J. C. , López-Brea M. 
Published: July 2002

ABSTRACT
VacA and CagA serological responses were detected in pediatric patients: 44 and 56%, respectively, in peptic ulcer (PU) patients, 33.3 and 44.4% in active chronic gastritis (ACG) patients, and 23.2 and 39.2% in non-ACG patients. Higher seroprevalence to CagA+VacA and to CagA+VacA+35-kDa antigen was found among PU patients. However, a low level of sensitivity and specificity was found for indirect detection of PU patients.
Recombinant Glycoprotein Vaccines for Human Immunodeficiency Virus-Infected Children and Their Effects on Viral Quasispecies
Authors: Essajee Shaffiq M. , Yogev Ram , Pollack Henry , Greenhouse Bryan , Krasinski Keith , Borkowsky William 
Published: July 2002

ABSTRACT
In individuals infected with human immunodeficiency virus type 1 (HIV-1), specific immunity is associated with a more diverse viral repertoire and slower disease progression. Attempts to enhance antiviral immunity with therapeutic vaccination have shown that recombinant glycoprotein (RGP) vaccines are safe, well tolerated, and immunogenic, but the effect of RGP vaccines on the viral repertoire is unknown. We evaluated diversification of the viral envelope in 12 HIV-infected children who received placebo or RGP vaccines. At baseline, 11 of 12 patients had multiple viral variants. On follow-up 6 months later, children who had a strong vaccine-associated lymphoproliferative immune response showed less viral diversification than those in whom the immune response was weak or absent. These results suggest that the immune response elicited by RGP vaccines does not exert a significant selection pressure on the viral quasispecies and therefore may not be helpful in changing the course of the disease.
Detection of
Cryptococcus neoformans
DNA in Tissue Samples by Nested and Real-Time PCR Assays
Authors: Bialek Ralf , Weiss Michael , Bekure-Nemariam Kubrom , Najvar Laura K. , Alberdi Maria B. , Graybill John R. , Reischl Udo 
Published: July 2002

ABSTRACT

Two PCR protocols targeting the 18S rRNA gene of
Cryptococcus neoformans
were established, compared, and evaluated in murine cryptococcal meningitis. One protocol was designed as a nested PCR to be performed in conventional block thermal cyclers. The other protocol was designed as a quantitative single-round PCR adapted to LightCycler technology. One hundred brain homogenates and dilutions originating from 20 ICR mice treated with different azoles were examined. A fungal burden of 3 × 10
1
to 2.9 × 10
4
CFU per mg of brain tissue was determined by quantitative culture. Specific PCR products were amplified by the conventional and the LightCycler methods in 86 and 87 samples, respectively, with products identified by DNA sequencing and real-time fluorescence detection. An analytical sensitivity of 1 CFU of
C. neoformans
per mg of brain tissue and less than 10 CFU per volume used for extraction was observed for both PCR protocols, while homogenates of 70 organs from mice infected with other fungi were PCR negative. Specificity testing was performed with genomic DNA from 31 hymenomycetous fungal species and from the ustilaginomycetous yeast
Malassezia furfur
, which are phylogenetically related to
C. neoformans
. Twenty-four strains, including species of human skin flora like
M. furfur
and
Trichosporon
spp., were PCR negative. Amplification was observed with
Cryptococcus amylolentus
,
Filobasidiella depauperata
,
Cryptococcus laurentii
, and five species unrelated to clinical specimens. LightCycler PCR products from
F. depauperata
and
Trichosporon faecale
could be clearly discriminated by melting curve analysis. The sensitive and specific nested PCR assay as well as the rapid and quantitative LightCycler PCR assay might be useful for the diagnosis and monitoring of human cryptococcal infections.
High Immunoglobulin G2 (IgG2) and Low IgG4 Levels Are Associated with Human Resistance toPlasmodium falciparumMalaria
Authors: Aucan Christophe , Traoré Yves , Tall François , Nacro Boubacar , Traoré-Leroux Thérèse , Fumoux Francis , Rihet Pascal 
Published: July 2002

ABSTRACTThere is accumulating evidence for a role of immunoglobulin G (IgG) in protection against malarial infection and disease. Only IgG1 and IgG3 are considered cytophilic and protective againstP. falciparum, whereas IgG2 and IgG4 were thought to be neither and even to block protective mechanisms. However, no clear pattern of association between isotypes and protection has so far emerged. We analyzed the isotypic distribution of the IgG response to conserved epitopes andP. falciparumblood-stage extract in 283 malaria-exposed individuals whose occurrence of infection and malaria attack had been monitored for about 1 year. Logistic regression analyses showed that, at the end of the season of transmission, high levels of IgG2 to RESA and to MSP2 epitopes were associated with low risk of infection. Indeed, IgG2 is able to bind FcγRIIA in individuals possessing the H131 allele, and we showed that 70% of the study subjects had this allele. Also, high specific IgG4 levels were associated with an enhanced risk of infection and with a high risk of malaria attack. Moreover, specific IgG2 and IgG3 levels, as well as the IgG2/IgG4 and IgG3/IgG4 ratios, increased with the age of subjects, in parallel with the protection against infection and disease. IgG4 likely competes with cytophilic antibodies for antigen recognition and may therefore block cytotoxicity mediated by antibody-activated effector cells. In conclusion, these results favor a protective role of IgG3 and IgG2, which may activate effector cells through FcγRIIA, and provide evidence for a blocking role of IgG4 in malarial infection and disease.
Iha: a Novel
Escherichia coli
O157:H7 Adherence-Conferring Molecule Encoded on a Recently Acquired Chromosomal Island of Conserved Structure
Authors: Tarr Phillip I. , Bilge Sima S. , Vary James C. , Jelacic Srdjan , Habeeb Rebecca L. , Ward Teresa R. , Baylor Michael R. , Besser Thomas E. 
Published: July 2002

ABSTRACT

The mechanisms used by Shiga toxin (Stx)-producing
Escherichia coli
to adhere to epithelial cells are incompletely understood. Two cosmids from an
E. coli
O157:H7 DNA library contain an adherence-conferring chromosomal gene encoding a protein similar to iron-regulated gene A (IrgA) of
Vibrio cholerae
(M. B. Goldberg, S. A. Boyko, J. R. Butterton, J. A. Stoebner, S. M. Payne, and S. B. Calderwood, Mol. Microbiol. 6:2407–2418, 1992). We have termed the product of this gene the IrgA homologue adhesin (Iha), which is encoded by
iha
. Iha is 67 kDa in
E. coli
O157:H7 and 78 kDa in laboratory
E. coli
and is structurally unlike other known adhesins. DNA adjacent to
iha
contains tellurite resistance loci and is conserved in structure in distantly related pathogenic
E. coli
, but it is absent from nontoxigenic
E. coli
O55:H7, sorbitol-fermenting Stx-producing
E. coli
O157:H−, and laboratory
E. coli
. We have termed this region the tellurite resistance- and adherence-conferring island. We conclude that Iha is a novel bacterial adherence-conferring protein and is contained within an
E. coli
chromosomal island of conserved structure. Pathogenic
E. coli
O157:H7 has only recently acquired this island.