bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biodegradation of
cis
-Dichloroethene as the Sole Carbon Source by a β-Proteobacterium
Authors: Coleman Nicholas V. , Mattes Timothy E. , Gossett James M. , Spain Jim C. 
Published: July 2002

ABSTRACT

An aerobic bacterium capable of growth on
cis-
dichloroethene (cDCE) as a sole carbon and energy source was isolated by enrichment culture. The 16S ribosomal DNA sequence of the isolate (strain JS666) had 97.9% identity to the sequence from
Polaromonas vacuolata
, indicating that the isolate was a β-proteobacterium. At 20°C, strain JS666 grew on cDCE with a minimum doubling time of 73 ± 7 h and a growth yield of 6.1 g of protein/mol of cDCE. Chloride analysis indicated that complete dechlorination of cDCE occurred during growth. The half-velocity constant for cDCE transformation was 1.6 ± 0.2 μM, and the maximum specific substrate utilization rate ranged from 12.6 to 16.8 nmol/min/mg of protein. Resting cells grown on cDCE could transform cDCE, ethene, vinyl chloride,
trans
-dichloroethene, trichloroethene, and 1,2-dichloroethane. Epoxyethane was produced from ethene by cDCE-grown cells, suggesting that an epoxidation reaction is the first step in cDCE degradation.
Use of an Attenuated Leishmanial Parasite as an Immunoprophylactic and Immunotherapeutic Agent against Murine Visceral Leishmaniasis
Authors: Mukhopadhyay Srirupa , Bhattacharyya Sandip , Majhi Ramdhan , De Tripti , Naskar Khudiram , Majumdar Subrata , Roy Syamal 
Published: July 2002

ABSTRACTThe ability of the leishmanial parasite UR6 to act as an immunoprophylactic and immunotherapeutic agent againstLeishmania donovaniinfection in BALB/c mice was investigated. Unlike the virulentL. donovaniAG83 (MOHOM/IN/1983/AG83), UR6 given through intracardiac route failed to induce visceral infection, but when it was injected subcutaneously, UR6 induced a short-lived and localized self-healing skin lesion. Priming of peritoneal macrophages with UR6 in vitro induced superoxide (O2−) generation, whereas similar experiments with virulent AG83 inhibited O2−generation. It was observed that priming of mice with either live or sonicated UR6 in the absence of any adjuvant provided strong protection against subsequent virulent challenge. Further, UR6-primed infected mice not only displayed a strong antileishmanial delayed-type hypersensitivity (DTH) response but also showed an elevated level of the serum antileishmanial immunoglobulin G2a (IgG2a) isotype, whereas infected mice failed to mount any antileishmanial DTH response and showed an elevated level of IgG1. This indicates that UR6 priming and subsequentL. donovaniinfection allowed the expansion of Th1 cells. Our studies indicate that UR6 has potential to be used as an immunoprophylactic and immunotherapeutic agent against experimental visceral leishmaniasis.
Measurement of Cytokine Secretion, Intracellular Protein Expression, and mRNA in Resting and Stimulated Peripheral Blood Mononuclear Cells
Authors: Sullivan Kathleen E. , Cutilli Joie , Piliero Lisa M. , Ghavimi-Alagha Darlene , Starr Stuart E. , Campbell Donald E. , Douglas Steven D. 
Published: July 2002

ABSTRACTQuantitation of cytokine production is a valuable adjunct to standard immunologic assays in defining several pathologic processes. Nevertheless, there is little agreement about which tissues should be assayed, which type of assay should be performed, and which stimulation protocol should be used. As these types of assays enter the clinical arena, there is need for standardization. There is also a need to maximize the amount of information which may be derived from a single sample. We compared secreted interleukin 4 (IL-4), IL-2, IL-6, tumor necrosis factor alpha (TNF-α), and gamma interferon proteins as measured by enzyme-linked immunosorbent assay with intracellular cytokine production (IL-2 and gamma interferon) as detected by flow cytometry and quantitative competitive PCR for IL-2, IL-4, TNF-α, and gamma interferon mRNA and cDNA. Results from unstimulated cells and cells stimulated with phorbol myristate acetate, phytohemagglutinin, and phorbol myristate acetate plus phytohemagglutin were compared. All three methodologies detected significant stimulation of cytokine production. The combination of phytohemagglutinin and phorbol myristate acetate was overall the most-potent stimulus.
Clarithromycin Attenuates Mastectomy-Induced Acute Inflammatory Response
Authors: Chow Louis W. C. , Yuen Kwok-Yung , Woo Patrick C. Y. , Wei William I. 
Published: July 2002

ABSTRACTBased on the observation that administration of clarithromycin led to an attenuation of the inflammatory response induced by surgical trauma in a guinea pig model, we investigated the potential beneficial effects of clarithromycin on the local and systemic inflammatory response in patients undergoing mastectomy in an open-label prospective study. During a 16-month period, 54 patients who underwent mastectomy were randomly divided into two groups. In one group, the patients received oral clarithromycin at a dose of 500 mg twice a day, from the day before to 3 days after mastectomy. There was no significant difference in the incidence of antibiotic prophylaxis-related toxicities or postoperative infections between the patients who received clarithromycin and those who did not. Clarithromycin treatment was significantly associated with an attenuation of febrile response, tachycardia, tachypnea, and an increase in monocyte counts (P, <0.0001, <0.01, <0.05, and <0.01, respectively). Clarithromycin also reduced the intensity and duration of postoperative pain (P, <0.05 and <0.005, respectively) and increased the range of motion of the involved shoulder (P< 0.05 for abduction and flexion). We conclude that clarithromycin effectively modulates the acute inflammatory response associated with mastectomy and produces a better clinical outcome.
Lipoteichoic Acid Inhibits Interleukin-2 (IL-2) Function by Direct Binding to IL-2
Authors: Plitnick Lisa M. , Jordan Robert A. , Banas Jeffrey A. , Jelley-Gibbs Dawn M. , Walsh Mary C. , Preissler Mark T. , Gosselin Edmund J. 
Published: July 2002

ABSTRACTLipoteichoic acid (LTA) is associated with the cell envelope of most gram-positive bacteria. Although previously thought to act mainly as a virulence factor by virtue of its adhesive nature, evidence is now provided that LTA can also suppress the function of interleukin-2 (IL-2), an autocrine growth factor for T cells. LTA from four separate bacterial strains lowered the levels of detectable IL-2 during a peripheral blood mononuclear cell response to the antigen tetanus toxoid (TT). T-cell proliferation in response to TT was similarly inhibited by LTA. In contrast, levels of detectable gamma interferon increased. In addition, LTA inhibited IL-2 detection by enzyme-linked immunosorbent assay (ELISA) and blocked the proliferative response of an IL-2-dependent T-cell line to soluble IL-2. Further studies using ELISA demonstrated that LTA blocks IL-2 detection and function by binding directly to IL-2. Flow cytometric analysis revealed that IL-2 binding to T cells is inhibited in the presence of purified LTA but not LTA plus anti-LTA monoclonal antibody. In summary, these studies demonstrate a novel effect of LTA on the immune response through direct binding to IL-2 and inhibition of IL-2 function. Importantly, gram-positive organisms from which LTA is obtained not only play an important role in the pathology of diseases such as bacterial endocarditis, septic shock, acute respiratory distress syndrome, and multiple organ failure but also comprise a significant portion of commensal populations within the human host. Inhibition of IL-2 function by LTA may represent yet another mechanism by which gram-positive bacteria dampen the host immune response and facilitate survival. Thus, LTA provides a potential target for therapeutic intervention when gram-positive organisms are involved.
Comparison of Dissociation-Enhanced Lanthanide Fluorescent Immunoassays to Enzyme-Linked Immunosorbent Assays for Detection of Staphylococcal Enterotoxin B,
Yersinia pestis
-Specific F1 Antigen, and Venezuelan Equine Encephalitis Virus
Authors: Smith Darci R. , Rossi Cynthia A. , Kijek Todd M. , Henchal Erik A. , Ludwig George V. 
Published: July 2002

ABSTRACT

The dissociation-enhanced lanthanide fluorescent immunoassays (DELFIA) were developed for the detection of staphylococcal enterotoxin B,
Yersinia pestis
-specific F1 antigen, and Venezuelan equine encephalitis virus. These assays were compared to previously developed enzyme-linked immunosorbent assays (ELISAs) by determining the sensitivity or limit of detection (LOD), the dynamic range, and the reproducibility of each assay in a number of different sample matrices. The sensitivity and specificity of each assay were then determined by using a small panel of blinded spiked and nonspiked samples. All three DELFIAs demonstrated at least 1 log greater sensitivity than corresponding ELISAs utilizing the same reagents and showed an increase in dynamic range of at least 2 log
10
concentrations. This increased LOD resulted in higher sensitivity rates for the DELFIA. The specificity of all of the assays evaluated was 100%, and no sample matrix effects were observed in either format. However, the reproducibility of the DELFIA was poor due to randomly distributed wells exhibiting excessive background signal (hot wells), which occurred throughout the evaluation. As this technology matures, the reproducibility of these assays should improve, as will the ability to identify hot wells. Despite its sensitivity, the logistical burden associated with the DELFIA and the technical expertise required to complete assays and interpret the data limit the application of this technology to reference or large clinical laboratories.
Chlamydia pneumoniae
Exacerbates Aortic Inflammatory Foci Caused by Murine Cytomegalovirus Infection in Normocholesterolemic Mice
Authors: Burian Katalin , Berencsi Klara , Endresz Valeria , Gyulai Zsofia , Valyi-Nagy Tibor , Valyi-Nagy Istvan , Bakay Marta , Geng Yuemei , Virok Dezso , Kari Laszlo , Hajnal-Papp Rozalia , Trinchieri Giorgio , Gonczol Eva 
Published: July 2002

ABSTRACT

Inflammatory foci induced by murine cytomegalovirus infection in normocholesterolemic mice were present temporarily in the aortic wall, but some of these foci developed into advanced lesions that persisted late after infection. The early foci induced by virus infection were significantly exacerbated following a single inoculation with
Chlamydia pneumoniae
.
Potential Benefit of Plasma Exchange in Treatment of Severe Icteric Leptospirosis Complicated by Acute Renal Failure
Authors: Tse Kai-Chung , Yip Pok-Siu , Hui King-Men , Li Fu-Keung , Yuen Kwok-Yung , Lai Kar-Neng , Chan Tak-Mao 
Published: July 2002

ABSTRACTLeptospirosis is a common zoonosis seen worldwide, but it is rare in our locality (Hong Kong). Clinical manifestations of leptospirosis are variable and may range from subclinical infection to fever, jaundice, hemorrhagic tendency, and fulminant hepato-renal failure. Severe hyperbilirubinemia and acute renal failure have been associated with high mortality. We report our experience with a patient who developed severe Weil's syndrome with marked conjugated hyperbilirubinemia and oliguric acute renal failure. These complications persisted despite treatment with penicillin and hemodiafiltration. Plasma exchange was instituted in view of the severe hyperbilirubinemia (970 μmol/liter). This was followed by prompt clinical improvement, with recovery of liver and renal function. The beneficial effects of plasma exchange could be attributed to amelioration of the toxic effects of hyperbilirubinemia on hepatocyte and renal tubular cell function. We conclude that plasma exchange should be considered as an adjunctive therapy for patients with severe icteric leptospirosis complicated by acute renal failure who have not shown rapid clinical response to conventional treatment.
Role of Novel Choline Binding Proteins in Virulence of
Streptococcus pneumoniae
Authors: Gosink Khoosheh K. , Mann Elizabeth R. , Guglielmo Chris , Tuomanen Elaine I. , Masure H. Robert 
Published: July 2002

ABSTRACT

The choline binding proteins (CBPs) are a family of surface proteins noncovalently bound to the phosphorylcholine moiety of the cell wall of
Streptococcus pneumoniae
by a conserved choline binding domain. Six new members of this family were identified, and these six plus two recently described cell wall hydrolases, LytB and LytC, were characterized for their roles in virulence. CBP-deficient mutants were constructed and tested for adherence to eukaryotic cells, colonization of the rat nasopharynx, and ability to cause sepsis. Five CBP mutants, CbpD, CbpE, CbpG, LytB, and LytC, showed significantly reduced colonization of the nasopharynx. For CbpE and -G this was attributable to a decreased ability to adhere to human cells. CbpG, a putative serine protease, also played a role in sepsis, the first observation of a pneumococcal virulence determinant strongly operative both on the mucosal surface and in the bloodstream.
Regulation of the
Porphyromonas gingivalis fimA
(Fimbrillin) Gene
Authors: Xie Hua , Chung Whasun O. , Park Yoonsuk , Lamont Richard J. 
Published: July 2002

ABSTRACT

In common with many bacterial virulence genes, the fimbrillin (
fimA
) gene of
Porphyromonas gingivalis
is modulated in response to environmental fluctuation. The
trans
-acting components that comprise the regulatory system for transcriptional activity of the
fimA
gene in
P. gingivalis
were investigated. Three major proteins were found to bind to the upstream region of the
fimA
promoter. One of these proteins was fimbrillin itself, and the other two were a major arginine protease (Rgp) and lysine protease (Kgp). Production of these proteins was necessary for maximal
fimA
transcription. An exogenous
fimA
promoter-
lacZ
reporter was inactive when introduced into a strain of
P. gingivalis
carrying a mutation in the indigenous
fimA
gene. Furthermore,
fimA
mRNA levels were significantly decreased in
rgp
and
kgp
mutant strains. These data indicate that
P. gingivalis
has evolved multiple levels of control of fimbrial gene expression to enhance its survival in hostile environments.
Identification of Discrete Domains within Gonococcal Transferrin-Binding Protein A That Are Necessary for Ligand Binding and Iron Uptake Functions
Authors: Boulton Ian C. , Yost Mary Kate , Anderson James E. , Cornelissen Cynthia Nau 
Published: July 2002

ABSTRACTThe availability of free iron in vivo is strictly limited, in part by the iron-binding protein transferrin. The pathogenicNeisseriaspp. can sequester iron from this protein, dependent upon two iron-repressible, transferrin-binding proteins (TbpA and TbpB). TbpA is a TonB-dependent, integral, outer membrane protein that may form a β-barrel exposing multiple surface loops, some of which are likely to contain ligand-binding motifs. In this study we propose a topological model of gonococcal TbpA and then test some of the hypotheses set forth by the model by individually deleting three putative loops (designated loops 4, 5, and 8). Each mutant TbpA could be expressed without toxicity and was surface exposed as assessed by immunoblotting, transferrin binding, and protease accessibility. Deletion of loop 4 or loop 5 abolished transferrin binding to whole cells in solid- and liquid-phase assays, while deletion of loop 8 decreased the affinity of the receptor for transferrin without affecting the copy number. Strains expressing any of the three mutated TbpAs were incapable of growth on transferrin as a sole iron source. These data implicate putative loops 4 and 5 as critical determinants for receptor function and transferrin-iron uptake by gonococcal TbpA. The phenotype of the ΔL8TbpA mutant suggests that high-affinity ligand interaction is required for transferrin-iron internalization.
Enzymatic Properties of Dipeptidyl Aminopeptidase IV Produced by the Periodontal PathogenPorphyromonas gingivalisand Its Participation in Virulence
Authors: Kumagai Yumi , Konishi Kiyoshi , Gomi Tomoharu , Yagishita Hisao , Yajima Ayako , Yoshikawa Masanosuke 
Published: July 2002

ABSTRACTPorphyromonas gingivalisis a major pathogen associated with adult periodontitis. We cloned and sequenced the gene (dpp) coding for dipeptidyl aminopeptidase IV (DPPIV) fromP. gingivalisW83, based on the amino acid sequences of peptide fragments derived from purified DPPIV. AnEscherichia colistrain overproducingP. gingivalisDPPIV was constructed. The enzymatic properties of recombinant DPPIV purified from the overproducer were similar to those of DPPIV isolated fromP. gingivalis. The three amino acid residues Ser, Asp, and His, which are thought to form a catalytic triad in the C-terminal catalytic domain of eukaryotic DPPIV, are conserved inP. gingivalisDPPIV. When each of the corresponding residues of the enzyme was substituted with Ala by site-directed mutagenesis, DPPIV activity significantly decreased, suggesting that these three residues ofP. gingivalisDPPIV are involved in the catalytic reaction. DPPIV-deficient mutants ofP. gingivaliswere constructed and subjected to animal experiments. Mice injected with the wild-type strain developed abscesses to a greater extent and died more frequently than those challenged with mutant strains. Mice injected with the mutants exhibited faster recovery from the infection, as assessed by weight gain and the rate of lesion healing. This decreased virulence of mutants compared with the parent strain suggests that DPPIV is a potential virulence factor ofP. gingivalisand may play important roles in the pathogenesis of adult periodontitis induced by the organism.
Construction and Characterization of an
agr
Deletion Mutant of
Staphylococcus epidermidis
Authors: Vuong Cuong , Götz Friedrich , Otto Michael 
Published: July 2002

ABSTRACT

The physiological significance of the accessory gene regulator (
agr
) system of
Staphylococcus epidermidis
was investigated by construction of an
agr
deletion mutant via allelic replacement with a spectinomycin resistance cassette. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the protein pattern was strongly altered in the mutant; the amounts of most surface proteins were higher, whereas the amounts of most exoproteins were lower. The
agr
system of
S. epidermidis
thus appears to have an important impact on growth phase-dependent protein synthesis as has been shown for
Staphylococcus aureus
. The activity of the exoenzymes lipase and protease, assumed to be involved in staphylococcal pathogenicity, was investigated by agar diffusion assays and SDS-PAGE activity staining. A general reduction of these enzyme activities in the
agr
mutant was found. The difference in overall lipase activity was small, but zymographic analysis suggested a clear defect in lipase processing in the
agr
mutant.
In Vitro and In Vivo Analyses of Constitutive and In Vivo-Induced Promoters in Attenuated Vaccine and Vector Strains of
Vibrio cholerae
Authors: John Manohar , Crean Thomas I. , Calderwood Stephen B. , Ryan Edward T. 
Published: July 2002

ABSTRACT

The optimal promoter for in vivo expression of heterologous antigens by live, attenuated vaccine vector strains of
Vibrio cholerae
is unclear; in vitro analyses of promoter activity may not accurately predict expression of antigens in vivo. We therefore introduced plasmids expressing the B subunit of cholera toxin (CtxB) under the control of a number of promoters into
V. cholerae
vaccine strain Peru2. We evaluated the
tac
promoter, which is constitutively expressed in
V. cholerae
, as well as the in vivo-induced
V. cholerae
heat shock
htpG
promoter and the in vivo-induced
V. cholerae
iron-regulated
irgA
promoter. The functionality of all promoters was confirmed in vitro. In vitro antigenic expression was highest in vaccine strains expressing CtxB under the control of the
tac
promoter (2 to 5 μg/ml/unit of optical density at 600 nm [OD
600
]) and, under low-iron conditions, in strains containing the
irgA
promoter (5 μg/ml/OD
600
). We orally inoculated mice with the various vaccine strains and used anti-CtxB immune responses as a marker for in vivo expression of CtxB. The vaccine strain expressing CtxB under the control of the
tac
promoter elicited the most prominent specific anti-CtxB responses in vivo (serum immunoglobulin G [IgG],
P
≤ 0.05; serum IgA,
P
≤ 0.05; stool IgA,
P
≤ 0.05; bile IgA,
P
≤ 0.05), despite the finding that the
tac
and
irgA
promoters expressed equivalent amounts of CtxB in vitro. Vibriocidal antibody titers were equivalent in all groups of animals. Our results indicate that in vitro assessment of antigen expression by vaccine and vector strains of
V. cholerae
may correlate poorly with immune responses in vivo and that of the promoters examined, the
tac
promoter may be best suited for expression from plasmids of at least certain heterologous antigens in such strains.
Tumor Necrosis Factor Alpha and Interleukin 1β Up-Regulate Gastric Mucosal Fas Antigen Expression inHelicobacter pyloriInfection
Authors: Houghton JeanMarie , Macera-Bloch Lisa S. , Harrison Lawrence , Kim Kyung H. , Korah Reju M. 
Published: July 2002

ABSTRACTFas-mediated gastric mucosal apoptosis is gaining attention as a cause of tissue damage due toHelicobacter pyloriinfection. We explored the effects ofH. pyloridirectly, and the effects of the inflammatory environment established subsequent toH. pyloriinfection, on Fas-mediated apoptosis in a nontransformed gastric mucosal cell line (RGM-1). Exposure toH. pylori-activated peripheral blood mononuclear cells (PBMCs), but notH. pyloriitself, induced Fas antigen (Fas Ag) expression, indicating a Fas-regulatory role for inflammatory cytokines in this system. Of various inflammatory cytokines tested, only interleukin 1β and tumor necrosis factor alpha induced Fas Ag expression, and removal of either of these from the conditioned medium abrogated the response. When exposed to Fas ligand, RGM-1 cells treated with PBMC-conditioned medium underwent massive and rapid cell death, interestingly, with a minimal effect on total cell numbers early on. Cell cycle analysis revealed a substantial increase in S phase cells among cells exposed to Fas ligand, suggesting an increase in their proliferative response. Taken together, these data indicate that the immune environment secondary toH. pyloriinfection plays a critical role in priming gastric mucosal cells to undergo apoptosis or to proliferate based upon their Fas Ag status.
Outer Membrane Protein A, Peptidoglycan-Associated Lipoprotein, and Murein Lipoprotein Are Released byEscherichia coliBacteria into Serum
Authors: Hellman Judith , Loiselle Paul M. , Tehan Megan M. , Allaire Jennifer E. , Boyle Lenora A. , Kurnick James T. , Andrews David M. , Sik Kim Kwang , Warren H. Shaw 
Published: July 2002

ABSTRACTComplexes containing lipopolysaccharide (LPS) and three outer membrane proteins (OMPs) are released by gram-negative bacteria incubated in human serum and into the circulation in an experimental model of sepsis. The same OMPs are bound by immunoglobulin G (IgG) in the cross-protective antiserum raised toEscherichia coliJ5 (anti-J5 IgG). This study was performed to identify the three OMPs. The 35-kDa OMP was identified as outer membrane protein A (OmpA) by immunoblotting studies using OmpA-deficient bacteria and recombinant OmpA protein. The 18-kDa OMP was identified as peptidoglycan-associated lipoprotein (PAL) based on peptide sequences from the purified protein and immunoblotting studies using PAL-deficient bacteria. The 5- to 9-kDa OMP was identified as murein lipoprotein (MLP) based on immunoblotting studies using MLP-deficient bacteria. The studies identify the OMPs released into human serum and into the circulation in an experimental model of sepsis as OmpA, PAL, and MLP.