bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Transport of Two Bacterial Strains in Intact Cores from Oyster, Virginia: Biological Effects and Numerical Modeling
Authors: Dong Hailiang , Rothmel Randi , Onstott Tullis C. , Fuller Mark E. , DeFlaun Mary F. , Streger Sheryl H. , Dunlap Robb , Fletcher Madilyn 
Published: July 2002

ABSTRACT

The transport characteristics of two adhesion-deficient, indigenous groundwater strains,
Comamonas
sp. strain DA001 and
Erwinia herbicola
OYS2-A, were studied by using intact sediment cores (7 by 50 cm) from Oyster, Va. Both strains are gram-negative rods (1.10 by 0.56 and 1.56 by 0.46 μm, respectively) with strongly hydrophilic membranes and a slightly negative surface charge. The two strains exhibited markedly different behaviors when they were transported through granular porous sediment. To eliminate any effects of physical and chemical heterogeneity on bacterial transport and thus isolate the biological effect, the two strains were simultaneously injected into the same core. DA001 cells were metabolically labeled with
35
S and tagged with a vital fluorescent stain, while OYS2-A cells were metabolically labeled with
14
C. The fast decay of
35
S allowed deconvolution of the two isotopes (and therefore the two strains). Dramatic differences in the transport behaviors were observed. The breakthrough of DA001 and the breakthrough of OYS2-A both occurred before the breakthrough of a conservative tracer (termed differential advection), with effluent recoveries of 55 and 30%, respectively. The retained bacterial concentration of OYS2-A in the sediment was twofold higher than that of DA001. Among the cell properties analyzed, the statistically significant differences between the two strains were cell length and diameter. The shorter, larger-diameter DA001 cells displayed a higher effluent recovery than the longer, smaller-diameter OYS2-A cells. CXTFIT modeling results indicated that compared to the DA001 cells, the OYS2-A cells experienced lower pore velocity, higher porosity, a higher attachment rate, and a lower detachment rate. All these factors may contribute to the observed differences in transport.
Decreasing the Level of Ethyl Acetate in Ethanolic Fermentation Broths ofEscherichia coliKO11 by Expression ofPseudomonas putida estZEsterase
Authors: Hasona Adnan , York S. W. , Yomano L. P. , Ingram L. O. , Shanmugam K. T. 
Published: July 2002

ABSTRACTDuring the fermentation of sugars to ethanol relatively high levels of an undesirable coproduct, ethyl acetate, are also produced. With ethanologenicEscherichia colistrain KO11 as the biocatalyst, the level of ethyl acetate in beer containing 4.8% ethanol was 192 mg liter−1. Although theE. coligenome encodes several proteins with esterase activity, neither wild-type strains nor KO11 contained significant ethyl acetate esterase activity. A simple method was developed to rapidly screen bacterial colonies for the presence of esterases which hydrolyze ethyl acetate based on pH change. This method allowed identification ofPseudomonas putidaNRRL B-18435 as a source of this activity and the cloning of a new esterase gene,estZ. Recombinant EstZ esterase was purified to near homogeneity and characterized. It belongs to family IV of lipolytic enzymes and contains the conserved catalytic triad of serine, aspartic acid, and histidine. As expected, this serine esterase was inhibited by phenylmethylsulfonyl fluoride and the histidine reagent diethylpyrocarbonate. The native and subunit molecular weights of the recombinant protein were 36,000, indicating that the enzyme exists as a monomer. By using α-naphthyl acetate as a model substrate, optimal activity was observed at pH 7.5 and 40°C. TheKmandVmaxfor α-naphthyl acetate were 18 μM and 48.1 μmol · min−1 · mg of protein−1, respectively. Among the aliphatic esters tested, the highest activity was obtained with propyl acetate (96 μmol · min−1 · mg of protein−1), followed by ethyl acetate (66 μmol · min−1 · mg of protein−1). Expression ofestZinE. coliKO11 reduced the concentration of ethyl acetate in fermentation broth (4.8% ethanol) to less than 20 mg liter−1.
Microtiter Plate Assay for Assessment of
Listeria monocytogenes
Biofilm Formation
Authors: Djordjevic D. , Wiedmann M. , McLandsborough L. A. 
Published: July 2002

ABSTRACT

Listeria monocytogenes
has the ability to form biofilms on food-processing surfaces, potentially leading to food product contamination. The objective of this research was to standardize a polyvinyl chloride (PVC) microtiter plate assay to compare the ability of
L. monocytogenes
strains to form biofilms. A total of 31 coded
L. monocytogenes
strains were grown in defined medium (modified Welshimer's broth) at 32°C for 20 and 40 h in PVC microtiter plate wells. Biofilm formation was indirectly assessed by staining with 1% crystal violet and measuring crystal violet absorbance, using destaining solution. Cellular growth rates and final cell densities did not correlate with biofilm formation, indicating that differences in biofilm formation under the same environmental conditions were not due to growth rate differences. The mean biofilm production of lineage I strains was significantly greater than that observed for lineage II and lineage III strains. The results from the standardized microtiter plate biofilm assay were also compared to biofilm formation on PVC and stainless steel as assayed by quantitative epifluorescence microscopy. Results showed similar trends for the microscopic and microtiter plate assays, indicating that the PVC microtiter plate assay can be used as a rapid, simple method to screen for differences in biofilm production between strains or growth conditions prior to performing labor-intensive microscopic analyses.
Differential Induction of Complement Fragment C5a and Inflammatory Cytokines during Intramammary Infections withEscherichia coliandStaphylococcus aureus
Authors: Riollet Céline , Rainard Pascal , Poutrel Bernard 
Published: July 2002

ABSTRACTThe prompt recruitment of neutrophils to the site of infection is essential for the defense of the bovine mammary gland against invading pathogens and is determinant for the outcome of the infection.Escherichia coliis known to induce clinical mastitis, characterized by an intense neutrophil recruitment leading to the eradication of the bacteria, whereasStaphylococcus aureusinduces subclinical mastitis accompanied by a moderate neutrophil recruitment and the establishment of chronic mastitis. To elicit the neutrophil recruitment into the udder, inflammatory mediators must be produced after recognition of the invading pathogen. To our knowledge, those mediators have never been studied duringS. aureusmastitis, although understanding of the neutrophil recruitment mechanisms could allow a better understanding of the differences in the pathogeneses elicited byE. coliandS. aureus. Therefore, we studied, at several time points, the accumulation of neutrophils and the presence of the chemoattractant complement fragment C5a and of the cytokines interleukin-1β (IL-1β), tumor necrosis factor alpha, and IL-8 in milk after inoculation ofE. coliorS. aureusin lactating bovine udders. The low levels of C5a and the absence of cytokines in milk fromS. aureus-infected cows, compared to the high levels found in milk fromE. coli-infected animals, mirror the differences in the severities of the two inflammatory reactions. The cytokine deficit in milk afterS. aureusinoculation in the lactating bovine mammary gland could contribute to the establishment of chronic mastitis. This result could help in the design of preventive or curative strategies against chronic mastitis.
Viability and Functional Activity of Cryopreserved Mononuclear Cells
Authors: Weinberg Adriana , Zhang Li , Brown Darby , Erice Alejo , Polsky Bruce , Hirsch Martin S. , Owens Susan , Lamb Karan 
Published: July 2002

ABSTRACT
Factors that influence viability and function of cryopreserved peripheral blood mononuclear cells (PBMC) were identified on 54 samples from 27 AIDS Clinical Trial Units. PBMC viability ranged from 1 to 96% with a median of 70%, was higher in laboratories with experienced staff, and was not significantly associated with CD4 cell number. Function of cryopreserved PBMC, measured by lymphocyte proliferation, was associated with viability. Preparations with viability greater than or equal to 70% had consistent proliferative responses and were suitable for functional analyses.
Defective Neutrophil Degranulation Induced by Interleukin-8 and Complement 5a and Down-Regulation of Associated Receptors in Children Vertically Infected with Human Immunodeficiency Virus Type 1
Authors: Meddows-Taylor Stephen , Kuhn Louise , Meyers Tammy M. , Sherman Gayle , Tiemessen Caroline T. 
Published: July 2002

ABSTRACTThe polymorphonuclear neutrophils (PMNs) of patients infected with human immunodeficiency virus type 1 (HIV-1) show impaired microbicidal responses. The present study assessed the functional integrity of PMN degranulation responses and the expression of specific receptors that mediate these responses in a group of children vertically infected with HIV-1. PMN degranulation in response to interleukin-8 (IL-8) and complement 5a (C5a) was measured in a group of HIV-1-infected children with mild and severe clinical disease and in an uninfected control group. In addition, the expression of CXCR1, CXCR2, and CD88 on whole-blood PMNs was quantified by flow cytometry. Although CXCR1 expression was found to be largely unaltered in the HIV-1-infected children relative to that in the control children, the intensity of CXCR2 expression was significantly reduced in those with severe disease. Furthermore, there was a significant reduction in the percentage of cells expressing CD88 and in the intensity of CD88 fluorescence in the HIV-1-infected children compared to that in control children, with CD88 fluorescence intensity more significantly reduced in the presence of severe disease. PMNs from a large proportion of the HIV-1-infected children either showed reciprocal degranulation responses or were unresponsive to IL-8 and C5a, whereas the PMNs from the uninfected children showed positive responses. Inefficient agonist-induced degranulation may contribute to the increased susceptibility of HIV-1-infected children to secondary microbial infections. Furthermore, reduced expression of CXCR2 and CD88 may be suggestive of defects in other functions of PMNs from HIV-1-infected children.
Western Immunoblotting with FiveTreponema pallidumRecombinant Antigens for Serologic Diagnosis of Syphilis
Authors: Sambri Vittorio , Marangoni Antonella , Eyer Christina , Reichhuber Christine , Soutschek Erwin , Negosanti Massimo , D'Antuono Antonietta , Cevenini Roberto 
Published: July 2002

ABSTRACTFive immunodominantTreponema pallidumrecombinant polypeptides (rTpN47, rTmpA, rTpN37, rTpN17, and rTpN15) were blotted onto strips, and 450 sera (200 from blood donors, 200 from syphilis patients, and 50 potentially cross-reactive) were tested to evaluate the diagnostic performance of recombinant Western blotting (recWB) in comparison with in-house whole-cell lysate antigen-based immunoblotting (wclWB) andT. pallidumhemagglutination (MHA-TP) for the laboratory diagnosis of syphilis. None of the serum specimens from blood donors or from potential cross-reactors gave a positive result when evaluated by recWB, wclWB, or MHA-TP. The evaluation of the immunoglobulin G immune response by recWB in sera from patients with different stages of syphilis showed that rTmpA was the most frequently identified antigen (95%), whereas only 41% of the specimens were reactive to rTpN37. The remaining recombinant polypeptides were recognized as follows: rTpN47, 92.5%; rTpN17, 89.5%; and rTpN15, 67.5%. The agreement between recWB and MHA-TP was 95.0% (100% with sera from patients with latent and late disease), and the concordance between wclWB and MHA-TP was 92.0%. The overall concordance between recWB and wclWB was 97.5% (100% with sera from patients with secondary and late syphilis and 94.6 and 98.6% with sera from patients with primary and latent syphilis, respectively). The overall sensitivity of recWB was 98.8% and the specificity was 97.1% with MHA-TP as the reference method. These values for sensitivity and specificity were slightly superior to those calculated for wclWB (sensitivity, 97.1%, and specificity, 96.1%). With wclWB as the standard test, the sensitivity and specificity of recWB were 98.9 and 99.3%, respectively. These findings suggest that the five recombinant polypeptides used in this study could be used as substitutes for the whole-cell lysateT. pallidumantigens and that this newly developed recWB test is a good, easy-to-use confirmatory method for the detection of syphilis antibodies in serum.
Bacteroides ovatusas the Predominant Commensal Intestinal Microbe Causing a Systemic Antibody Response in Inflammatory Bowel Disease
Authors: Saitoh Shin , Noda Satoshi , Aiba Yuji , Takagi Atsushi , Sakamoto Mitsuo , Benno Yoshimi , Koga Yasuhiro 
Published: July 2002

ABSTRACTTo clarify what bacterial species of commensal intestinal microbes are recognized as the antigens that induce a serum antibody response in patients with inflammatory bowel disease (IBD), 72 subjects consisting of 12 Crohn’s disease patients, 30 ulcerative colitis patients, and 30 healthy volunteers were examined for their titers of serum antibody to these intestinal bacteria. In IBD patients, as a result, significant elevations of both the immunoglobulin G (IgG) and IgA titers toBacteroides ovatuswere found. Immunoblotting showed that a definite 19.5-kDa band ofB. ovatuswas bound to the serum antibody raised in IBD patients. It was thus concluded thatB. ovatuscauses serum antibody responses in IBD patients, and a 19.5-kDa molecule of this bacterium appears to be the responsible antigen, although the role of this event in pathogenesis remains unclear.
Dependence of Bacterial Protein Adhesins on Toll-Like Receptors for Proinflammatory Cytokine Induction
Authors: Hajishengallis George , Martin Michael , Sojar Hakimuddin T. , Sharma Ashu , Schifferle Robert E. , DeNardin Ernesto , Russell Michael W. , Genco Robert J. 
Published: July 2002

ABSTRACTToll-like receptors (TLRs) are important signal transducers that mediate inflammatory reactions induced by microbes through pattern recognition of virulence molecules such as lipopolysaccharide (LPS) and lipoproteins. We investigated whether proinflammatory cytokine responses induced by certain bacterial protein adhesins may also depend on TLRs. In differentiated THP-1 mononuclear cells stimulated by LPS-free recombinant fimbrillin (rFimA) fromPorphyromonas gingivalis, cytokine release was abrogated by monoclonal antibodies (MAbs) to CD14 and TLR4 but not to TLR2. Similar experiments using anti-β2 integrin MAbs suggested that β2 integrins (CD11/CD18) also play a role in cytokine induction by rFimA or native fimbriae. Minor fimbriae (distinct from thefimA-encoded major fimbriae) ofP. gingivalisinduced proinflammatory cytokine release in a CD14- and TLR2-dependent mode. Cytokine induction by BspA, a leucine-rich repeat protein fromBacteroides forsythus, depended heavily on CD14 and TLR2. We also found that the ability of the streptococcal protein AgI/II to stimulate cytokine release depended partially on CD14 and TLR4, and the AgI/II segment that possibly interacts with these receptors was identified as its N-terminal saliva-binding region. When THP-1 cells were exposed to rFimA for 24 h, surface expression of CD14 and CD18 was decreased and the cells became hyporesponsive to cytokine induction by a second challenge with rFimA. However, tolerance induction was abolished when the THP-1 cells were pretreated with rFimA in the presence of either anti-CD14 MAb or anti-TLR4 MAb. Induction of cross-tolerance between rFimA and LPS correlated with downregulation of the pattern recognition receptors involved. Our data suggest that the CD14-TLR2/4 system is involved in cytokine production and tolerance induction upon interaction with certain proinflammatory bacterial protein adhesins.
Systemic Inflammation in Cardiovascular and Periodontal Disease: Comparative Study
Authors: Glurich Ingrid , Grossi Sara , Albini Boris , Ho Alex , Shah Rashesh , Zeid Mohamed , Baumann Heinz , Genco Robert J. , De Nardin Ernesto 
Published: July 2002

ABSTRACTEpidemiological studies have implicated periodontal disease (PD) as a risk factor for the development of cardiovascular disease (CVD). These studies addressed the premise that local infection may perturb the levels of systemic inflammatory mediators, thereby promoting mechanisms of atherosclerosis. Levels of inflammatory mediators in the sera of subjects with only PD, only CVD, both diseases, or neither condition were compared. Subjects were assessed for levels of C-reactive protein (CRP), serum amyloid A (SAA), ceruloplasmin, α1-acid-glycoprotein (AAG), α1-antichymotrypsin (ACT), and the soluble cellular adhesion molecules sICAM-1 and sVCAM by enzyme-linked immunoabsorbent and/or radial immunodiffusion assays. CRP levels in subjects with either condition alone were elevated twofold above subjects with neither disease, whereas a threefold increase was noted in subjects with both diseases (P= 0.0389). Statistically significant increases in SAA and ACT were noted in subjects with both conditions compared to those with one or neither condition (P= 0.0162 and 0.0408, respectively). Ceruloplasmin levels were increased in subjects with only CVD (P= 0.0001). Increases in sVCAM levels were noted in all subjects with CVD (P= 0.0054). No differences in sICAM levels were noted among subject groups. A trend toward higher levels of AAG was noted in subjects with both conditions and for ACT in subjects with only PD. Immunohistochemical examination of endarterectomy specimens of carotid arteries from subjects with atherosclerosis documented SAA and CRP deposition in association with atheromatous lesions. The data support the hypothesis that localized persistent infection may influence systemic levels of inflammatory mediators. Changes in inflammatory mediator levels potentially impact inflammation-associated atherosclerotic processes.
Increased Numbers of ESAT-6- and Purified Protein Derivative-Specific Gamma Interferon-Producing Cells in Subclinical and Active Tuberculosis Infection
Authors: Ulrichs Timo , Anding Peter , Porcelli Steven , Kaufmann Stefan H. E. , Munk Martin E. 
Published: July 2002

ABSTRACT

Numbers of gamma interferon (IFN-γ)-producing cells reactive to ESAT-6 antigen were increased in recent converters to purified protein derivative positivity and in tuberculosis patients but not in unvaccinated or
Mycobacterium bovis
BCG-vaccinated healthy donors. ESAT-6-reactive IFN-γ-producing cells in recent converters and tuberculosis patients recognized similar synthetic peptides. Thus, ESAT-6 is a potential candidate for use in detection of early, as well as active, tuberculosis and for control of the disease.
Intranasal Immunization of Mice with a Mixture of the Pneumococcal Proteins PsaA and PspA Is Highly Protective against Nasopharyngeal Carriage ofStreptococcus pneumoniae
Authors: Briles David E. , Ades Eddie , Paton James C. , Sampson Jacquelyn S. , Carlone George M. , Huebner Robert C. , Virolainen Anni , Swiatlo Edwin , Hollingshead Susan K. 
Published: July 2002

ABSTRACTAcquisition of pneumococci is generally from carriers rather than from infected individuals. Therefore, to induce herd immunity againstStreptococcus pneumoniaeit will be necessary to elicit protection against carriage. Capsular polysaccharide-protein conjugates, PspA, and PsaA are known to elicit some protection against nasopharyngeal carriage of pneumococci but do not always completely eliminate carriage. In this study, we observed that PsaA elicited better protection than did PspA against carriage. Pneumolysin elicited no protection against carriage. Immunization with a mixture of PsaA and PspA elicited the best protection against carriage. These results indicate that PspA and PsaA may be useful for the elicitation of herd immunity in humans. As PspA and pneumolysin are known to elicit immunity to bacteremia and pneumonia, their inclusion in a mucosal vaccine may enable such a vaccine to prevent invasive disease as well as carriage.
Direct Quantitative Transcript Analysis of the
agr
Regulon of
Staphylococcus aureus
during Human Infection in Comparison to the Expression Profile In Vitro
Authors: Goerke Christiane , Campana Silvia , Bayer Manfred G. , Döring Gerd , Botzenhart Konrad , Wolz Christiane 
Published: July 2002

ABSTRACT

Bacteria possess a repertoire of distinct regulatory systems promoting survival in disparate environments. Under in vitro conditions it was demonstrated for the human pathogen
Staphylococcus aureus
that the expression of most virulence factors is coordinated by the global regulator
agr
. To monitor bacterial gene regulation in the host, we developed a method for direct transcript analysis from clinical specimens. Quantification of specific transcripts was performed by competitive reverse transcription-PCR, and results were normalized against the constitutively expressed gene for gyrase (
gyr
). Using sputum from cystic fibrosis (CF) patients infected with
S. aureus
we examined the transcription of the effector molecule RNAIII of
agr
, of
spa
(protein A), generally repressed by
agr
, and of
hla
(alpha-toxin), generally activated by
agr
. In the CF lung RNAIII was expressed poorly, indicating an inactive
agr
in vivo. Despite the low level of RNAIII expression,
spa
was detectable only in minute amounts and an irregular transcription of
hla
was observed in all sputum samples. After subculturing of patient strains
agr
-deficient isolates and isolates with unusual expression profiles, i.e., not consistent with those obtained from prototypic strains, were observed. In conclusion, the
agr
activity seems to be nonessential in CF, and from the described expression pattern of
spa
and
hla
, other regulatory circuits aside from
agr
are postulated in vivo.