bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation of Branched-Chain Fatty Acids Marks the Normal Physiological Range for Growth in
Listeria monocytogenes
Authors: Nichols David S. , Presser Kirsty A. , Olley June , Ross Tom , McMeekin Tom A. 
Published: July 2002

ABSTRACT

The fatty acid composition of
Listeria monocytogenes
Scott A was determined by close-interval sampling over the entire biokinetic temperature range. There was a high degree of variation in the percentage of branched-chain fatty acids at any given temperature. The percentage of branched C
17
components increased with growth temperature in a linear manner. However, the percentages of iso-C
15:0
(i15:0) and anteiso-C
15:0
(a15:0) were well described by third-order and second-order polynomial curves, respectively. There were specific temperature regions where the proportion of branched-chain fatty acids deviated significantly from the trend established over the entire growth range. In the region from 12 to 13°C there were significant deviations in the percentages of both i15:0 and a15:0 together with a suggested deviation in a17:0, resulting in a significant change in the total branched-chain fatty acids. In the 31 to 33°C region the percentage of total branched-chain components exhibited a significant deviation. The observed perturbations in fatty acid composition occurred near the estimated boundaries of the normal physiological range for growth.
Naturally Acquired Antibody Responses to the C-Terminal Region of Merozoite Surface Protein 1 ofPlasmodium vivaxin Korea
Authors: Park Jae-Won , Moon Seung-Hwan , Yeom Joon-Sup , Lim Kook-Jin , Sohn Mi-Jin , Jung Woo-Chul , Cho Young-Jung , Jeon Ki-Won , Ju Woong , Ki Chang-Seok , Oh Myoung-Don , Choe Kangwon 
Published: July 2002

ABSTRACTWe expressed a protein inSaccharomyces cerevisiaein order to evaluate the humoral immune responses to the C-terminal region of the merozoite surface protein 1 ofPlasmodium vivax. This protein (Pv20018) had a molecular mass of 18 kDa and was reactive with the sera of individuals with patent vivax malaria on immunoblotting analysis. The levels of immunoglobulin M (IgM) and IgG antibodies against Pv20018were measured in 421 patients with vivax malaria (patient group), 528 healthy individuals from areas of nonendemicity (control group 1), and 470 healthy individuals from areas of endemicity (control group 2), using the indirect enzyme-linked immunosorbent assay (ELISA) method. To study the longevity of the antibodies, 20 subjects from the patient group were also tested for the antibody levels once a month for 1 year. When the cutoff values for seropositivity were determined as the mean + 3 × standard deviation of the antibody levels in control group 1, both IgG and IgM antibody levels were negative in 98.5% (465 of 472) of control group 2. The IgG and IgM antibodies were positive in 88.1% (371 of 421) and 94.5% (398 of 421) of the patient group, respectively. The IgM antibody became negative 2 to 4 months after the onset of symptoms, whereas the IgG antibody usually remained positive for more than 5 months. In conclusion, indirect ELISA using Pv20018expressed inS. cerevisiaemay be a useful diagnostic method for vivax malaria.
Specificities and Sensitivities of Four Monoclonal Antibodies for Typing of
Borrelia burgdorferi
Sensu Lato Isolates
Authors: Bretz A. G. , Ryffel K. , Hutter P. , Dayer E. , Péter O. 
Published: July 2002

ABSTRACT

Borrelia burgdorferi
, the agent of Lyme borreliosis, is genetically more heterogeneous than previously thought. In Europe five genospecies have been described from the original
B. burgdorferi
sensu lato (sl):
B. burgdorferi
sensu stricto (ss),
B. garinii, B. afzelii, B. lusitaniae
, and
B. valaisiana
. In the United States,
B. burgdorferi
ss as well as
B. bissettii
in California and
B. andersonii
on the East Coast were differentiated. In Asia,
B. japonica
has been identified along, with
B. garinii, B. afzelii
, and
B. valaisiana
. In order to evaluate sensitivity and specificity of four species-specific monoclonal antibodies, we analyzed 210
B. burgdorferi
sl isolates belonging to eight genospecies by immunoblot and confirmed genospecies by restriction fragment length polymorphism (RFLP) of
rrf
(5S)-
rrl
(23S) intergenic spacer amplicon. Monoclonal antibody H3TS had 100% sensitivity for 55
B. burgdorferi ss
isolates but showed reactivity with all four isolates belonging to
B. bissetii
. Monoclonal antibody I 17.3 showed 100% specificity and sensitivity for 45
B. afzelii
isolates. Monoclonal antibody D6 was 100% specific for
B. garinii
but missed 1 of 64 isolates (98.5% sensitivity). Monoclonal antibody A116k was 100% specific for
B. valaisiana
but was unreactive with 4 of 24 isolates (83.5% sensitivity). Genetic analysis correlated well with results of reactivity and confirmed efficacy of the phenotypic typing of these antibodies. Some isolates showed atypical RFLP. Therefore, both phenotypic and genotypic analyses are needed to characterize new
Borrelia
isolates.
Reverse Transcriptase-PCR Analysis of Bacterial rRNA for Detection and Characterization of Bacterial Species in Arthritis Synovial Tissue
Authors: Kempsell Karen E. , Cox Charles J. , Hurle Michael , Wong Anthony , Wilkie Scott , Zanders Edward D. , Gaston J. S. Hill , Crowe J. Scott 
Published: July 2002

ABSTRACT
Onset of rheumatoid arthritis (RA) is widely believed to be preceded by exposure to some environmental trigger such as bacterial infectious agents. The influence of bacteria on RA disease onset or pathology has to date been controversial, due to inconsistencies between groups in the report of bacterial species isolated from RA disease tissue. Using a modified technique of reverse transcriptase-PCR amplification, we have detected bacterial rRNA in the synovial tissue of late-stage RA and non-RA arthritis controls. This may be suggestive of the presence of live bacteria. Sequencing of cloned complementary rDNA (crDNA) products revealed a number of bacterial sequences in joint tissue from each patient, and from these analyses a comprehensive profile of the organisms present was compiled. This revealed a number of different organisms in each patient, some of which are common to both RA and non-RA controls and are probably opportunistic colonizers of previously diseased tissue and others which are unique species. These latter organisms may be candidates for a specific role in disease pathology and require further investigation to exclude them as causative agents in the complex bacterial millieu. In addition, many of the detected bacterial species have not been identified previously from synovial tissue or fluid from arthritis patients. These may not be easily cultivable, since they were not revealed in previous studies using conventional in vitro bacterial culture methods. In situ hybridization analyses have revealed the joint-associated bacterial rRNA to be both intra- and extracellular. The role of viable bacteria or their nucleic acids as triggers in disease onset or pathology in either RA or non-RA arthritis controls is unclear and requires further investigation.
Relationship of Blood Group Determinants on
Helicobacter pylori
Lipopolysaccharide with Host Lewis Phenotype and Inflammatory Response
Authors: Heneghan Michael A. , McCarthy Ciaran F. , Moran Anthony P. 
Published: July 2002

ABSTRACT

As Lewis a (Le
a
) and Lewis b (Le
b
) blood group antigens are isoforms of Lewis x (Le
x
) and Lewis y (Le
y
) and are expressed in the gastric mucosa, we evaluated whether the patterns of expression of Le
x
and Le
y
on
Helicobacter pylori
lipopolysaccharides reflected those of host expression of Le
a
and Le
b
. When 79 patients (secretors and nonsecretors) were examined for concordance between bacterial and host Le expression, no association was found (χ
2
= 5.734, 3 df,
P
= 0.125), nor was there a significant difference between the amount of Le
x
or Le
y
expressed on isolates from ulcer and chronic gastritis patients (
P
> 0.05). Also, the effect of host and bacterial expression of Le antigens on bacterial colonization and the observed inflammatory response was assessed. In ulcer patients, Le
x
expression was significantly related to neutrophil infiltration (
r
s
= 0.481,
P
= 0.024), whereas in chronic gastritis patients significant relationships were found between Le
x
expression and
H. pylori
colonization density (
r
s
= 0.296,
P
= 0.03), neutrophil infiltrate (
r
s
= 0.409,
P
= 0.001), and lymphocyte infiltrate (
r
s
= 0.389,
P
= 0.002). Furthermore, bacterial Le
y
expression was related to neutrophil (
r
s
= 0.271,
P
= 0.033) and lymphocyte (
r
s
= 0.277,
P
= 0.029) infiltrates. Thus, although no evidence of concordance was found between bacterial and host expression of Le determinants, these antigens may be crucial for bacterial colonization, and the ensuing inflammatory response appears, at least in part, to be influenced by Le antigens.
Tumor Necrosis Factor Receptor p55-Deficient Mice Respond to AcuteYersinia enterocoliticaInfection with Less Apoptosis and More Effective Host Resistance
Authors: Zhao Yi-Xue , Lajoie Ginette , Zhang Hongwei , Chiu Basil , Payne Ursula , Inman Robert D. 
Published: July 2002

ABSTRACTTumor necrosis factor (TNF) has generally been regarded as a protective cytokine in host defense against bacterial infections. In the present study, we evaluated the role of TNF in the acute phase of infection byYersinia enterocoliticaby using mice rendered genetically deficient in TNF receptor p55 (TNFRp55−/−). Unexpectedly, TNFRp55−/−mice showed more effective resistance to the bacteria, reflected in enhanced bacterial clearance and less tissue damage, than did control C57BL/6 mice. C57BL/6 mice showed evidence of extensive apoptosis in the spleen accompanied by a selective decrease in the CD4+-T-cell population of splenocytes, whereas TNFRp55−/−mice were spared these changes. The splenocytes from TNFRp55−/−mice also maintained a robust gamma interferon IFN-γ response to mitogenic stimulation, while the comparable response in C57BL/6 mice was impaired. In addition, splenocytes harvested from infected mice demonstrated lower production of interleukin-10 IL-10 in TNFRp55−/−mice than in C57BL/6 mice. These findings suggest thatYersiniacan induce TNFRp55-mediated apoptosis of splenocytes in the acute phase of the infection and that alteration of T-cell-generated cytokines can dramatically alter the early events in host defense against this pathogen.
Bordetella pertussisVirulence Factors Affect Phagocytosis by Human Neutrophils
Authors: Weingart Christine L. , Weiss Alison A. 
Published: July 2002

ABSTRACTThe interaction between human neutrophils and wild-typeBordetella pertussisor mutants expressing altered lipopolysaccharide or lacking virulence factors—pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, filamentous hemagglutinin (FHA), pertactin, or BrkA—was examined. In the absence of antibodies, the wild-type strain and the mutants, with the exception of mutants lacking FHA, attached efficiently to neutrophils. The addition of opsonizing antibodies caused a significant reduction (approximately 50%) in attachment of the wild-type strain and most of the mutants expressing FHA, suggesting that bacterium-mediated attachment is more efficient than Fc-mediated attachment. Phagocytosis was also examined. In the absence of antibodies, about 12% of the wild-type bacteria were phagocytosed. Opsonization caused a statistically significant reduction in phagocytosis (to 3%), possibly a consequence of reduced attachment. Phagocytosis of most of the mutants was similar to that of the wild type, with the exception of the mutants lacking adenylate cyclase toxin. About 70% of the adenylate cyclase toxin mutants were phagocytosed, but only in the presence of opsonizing antibody, suggesting that Fc receptor-mediated signaling may be needed for phagocytosis. These studies indicate that FHA mediates attachment ofB. pertussisto neutrophils, but adenylate cyclase toxin blocks phagocytosis.
Listeria monocytogenes-Infected Human Dendritic Cells: Uptake and Host Cell Response
Authors: Kolb-Mäurer Annette , Gentschev Ivaylo , Fries Hans-Werner , Fiedler Franz , Bröcker Eva-Bettina , Kämpgen Eckhart , Goebel Werner 
Published: July 2002

ABSTRACTDendritic cells (DCs) are potent antigen-presenting cells and play a crucial role in initiation and modulation of specific immune responses. Various pathogens are able to persist inside DCs. However, internalization of the gram-positive bacteriumListeria monocytogenesinto human DCs has not yet been shown. In the present study, we demonstrate that human monocyte-derived immature DCs can efficiently phagocytoseL. monocytogenes. This uptake is independent of listerial adhesion factors internalin A and internalin B but requires cytoskeletal motion and factors present in human plasma. A major portion of internalized bacteria is found in membrane-bound phagosomes and is rarely free in the cytosol, as shown by transmission electron microscopy and by using anL. monocytogenesstrain expressing green fluorescent protein when in the host cell cytosol. The infection caused maturation of the immature DCs into mature DCs displaying high levels of CD83, CD25, major histocompatibility complex class II, and the CD86 costimulator molecule. This effect appeared to be largely mediated by listerial lipoteichoic acid. AlthoughL. monocytogenesinfection is known to induce death in other cell types, infection of human DCs was found to induce necrotic but not apoptotic death in fewer than 20% of DCs. Therefore, the ability of DCs to act as effective antigen-presenting cells for listerial immunity is probably enhanced by their resistance to cell death, as well as their ability to rapidly differentiate into mature, immunostimulatory DCs upon encountering bacteria.
Haemophilus influenzaePorin Contributes to Signaling of the Inflammatory Cascade in Rat Brain
Authors: Galdiero Massimiliano , D'Amico Michele , Gorga Fernanda , Di Filippo Clara , D'Isanto Marina , Vitiello Mariateresa , Longanella Anna , Tortora Annalisa 
Published: July 2002

ABSTRACTIn the present study we observed that theHaemophilus influenzaetype b (Hib) porin, among the different surface bacterial components, is involved in the pathophysiology of bacterial meningitis. This study demonstrates that inoculation of Hib porin into the fourth cerebral ventricle causes the simultaneous expression of interleukin-1α (IL-1α), tumor necrosis factor alpha (TNF-α), and macrophage inflammatory protein 2 (MIP-2) at 6 h after inoculation. At 24 h, the expression of MIP-2 decreases while the expression of IL-1α and TNF-α increases. The mRNA expression of IL-1α, TNF-α, and MIP-2 is correlated with injury to the blood-brain barrier as demonstrated by the appearance of serum proteins and leukocytes in cerebrospinal fluid and by the increase in brain water content.
High Extracellular Levels of
Mycobacterium tuberculosis
Glutamine Synthetase and Superoxide Dismutase in Actively Growing Cultures Are Due to High Expression and Extracellular Stability Rather than to a Protein-Specific Export Mechanism
Authors: Tullius Michael V. , Harth Günter , Horwitz Marcus A. 
Published: July 2002

ABSTRACT

Glutamine synthetase (GS) and superoxide dismutase (SOD), large multimeric enzymes that are thought to play important roles in the pathogenicity of
Mycobacterium tuberculosis
, are among the bacterium's major culture filtrate proteins in actively growing cultures. Although these proteins lack a leader peptide, their presence in the extracellular medium during early stages of growth suggested that they might be actively secreted. To understand their mechanism of export, we cloned the homologous genes (
glnA1
and
sodA
) from the rapid-growing, nonpathogenic
Mycobacterium smegmatis
, generated
glnA1
and
sodA
mutants of
M. smegmatis
by allelic exchange, and quantitated expression and export of both mycobacterial and nonmycobacterial GSs and SODs in these mutants. We also quantitated expression and export of homologous and heterologous SODs from
M. tuberculosis
. When each of the genes was expressed from a multicopy plasmid,
M. smegmatis
exported comparable proportions of both the
M. tuberculosis
and
M. smegmatis
GSs (in the
glnA1
strain) or SODs (in the
sodA
strain), in contrast to previous observations in wild-type strains. Surprisingly, recombinant
M. smegmatis
and
M. tuberculosis
strains even exported nonmycobacterial SODs. To determine the extent to which export of these large, leaderless proteins is expression dependent, we constructed a recombinant
M. tuberculosis
strain expressing green fluorescent protein (GFP) at high levels and a recombinant
M. smegmatis
strain coexpressing the
M. smegmatis
GS,
M. smegmatis
SOD, and
M. tuberculosis
BfrB (bacterioferritin) at high levels. The recombinant
M. tuberculosis
strain exported GFP even in early stages of growth and at proportions very similar to those of the endogenous
M. tuberculosis
GS and SOD. Similarly, the recombinant
M. smegmatis
strain exported bacterioferritin, a large (∼500-kDa), leaderless, multimeric protein, in proportions comparable to GS and SOD. In contrast, high-level expression of the large, leaderless, multimeric protein malate dehydrogenase did not lead to extracellular accumulation because the protein was highly unstable extracellularly. These findings indicate that, contrary to expectations, export of
M. tuberculosis
GS and SOD in actively growing cultures is not due to a protein-specific export mechanism, but rather to bacterial leakage or autolysis, and that the extracellular abundance of these enzymes is simply due to their high level of expression and extracellular stability. The same determinants likely explain the presence of other leaderless proteins in the extracellular medium of actively growing
M. tuberculosis
cultures.
Epitope Mapping of Neutralizing Botulinum Neurotoxin A Antibodies by Phage Display
Authors: Mullaney B. P. , Pallavicini M. G. , Marks J. D. 
Published: July 2002

ABSTRACT
Single-chain antibodies neutralize activity and bind nonoverlapping epitopes of botulinum A neurotoxin. Two phage display epitope libraries were constructed from the 1.3 kb of binding domain cDNA. The minimal epitopes selected against the single-chain Fv-Fc antibodies correspond to conformational epitopes with amino acid residues 1115 to 1223 (S25), 1131 to 1264 (3D12), and 889 to 1294 (C25).
Salmonella enterica
Serovar Typhi Possesses a Unique Repertoire of Fimbrial Gene Sequences
Authors: Townsend Stacy M. , Kramer Naomi E. , Edwards Robert , Baker Stephen , Hamlin Nancy , Simmonds Mark , Stevens Kim , Maloy Stanley , Parkhill Julian , Dougan Gordon , Bäumler Andreas J. 
Published: July 2002

ABSTRACT

Salmonella enterica
serotype Typhi differs from nontyphoidal
Salmonella
serotypes by its strict host adaptation to humans and higher primates. Since fimbriae have been implicated in host adaptation, we investigated whether the serotype Typhi genome contains fimbrial operons which are unique to this pathogen or restricted to typhoidal
Salmonella
serotypes. This study established for the first time the total number of fimbrial operons present in an individual
Salmonella
serotype. The serotype Typhi CT18 genome, which has been sequenced by the Typhi Sequencing Group at the Sanger Centre, contained a type IV fimbrial operon, an orthologue of the
agf
operon, and 12 putative fimbrial operons of the chaperone-usher assembly class. In addition to
sef, fim, saf
, and
tcf
, which had been described previously in serotype Typhi, we identified eight new putative chaperone-usher-dependent fimbrial operons, which were termed
bcf, sta, stb, ste, std, stc, stg
, and
sth
. Hybridization analysis performed with 16 strains of
Salmonella
reference collection C and 22 strains of
Salmonella
reference collection B showed that all eight putative fimbrial operons of serotype Typhi were also present in a number of nontyphoidal
Salmonella
serotypes. Thus, a simple correlation between host range and the presence of a single fimbrial operon seems at present unlikely. However, the serotype Typhi genome differed from that of all other
Salmonella
serotypes investigated in that it contained a unique combination of putative fimbrial operons.
Contribution of CD8+T Cells to Gamma Interferon Production in Human Tuberculosis
Authors: Shams Homayoun , Wizel Benjamin , Weis Stephen E. , Samten Buka , Barnes Peter F. 
Published: July 2002

ABSTRACTThe proportions of peripheral blood mononuclear cells (PBMC), CD4+T cells, and CD8+T cells that produce gamma interferon (IFN-γ) in response toMycobacterium tuberculosiswere markedly reduced in tuberculosis patients, particularly in those with severe disease. Depletion of CD4+but not CD8+cells prior to stimulation of PBMC withM. tuberculosisabolished IFN-γ production. These results show that (i) IFN-γ production by CD8+and CD4+cells correlates with the clinical manifestations ofM. tuberculosisinfection and (ii) IFN-γ production by CD8+cells depends on CD4+cells.
Cloned Shiga Toxin 2 B Subunit Induces Apoptosis in Ramos Burkitt's Lymphoma B Cells
Authors: Marcato Paola , Mulvey George , Armstrong Glen D. 
Published: July 2002

ABSTRACTThe Shiga toxins (Stx1 and Stx2), produced byShigella dysenteriaetype 1 and enterohemorrhagicEscherichia coli, consist of one A subunit and five B subunits. The Stx1 and Stx2 B subunits form a pentameric structure that binds to globotriaosylceramide (Gb3-Cer) receptors on eukaryotic cells and promotes endocytosis. The A subunit then inhibits protein biosynthesis, which triggers apoptosis in the affected cell. In addition to its Gb3-Cer binding activity, the data in the following report demonstrate that the Stx2 B pentamer induces apoptosis in Ramos Burkitt's lymphoma B cells independently of A subunit activity. Apoptosis was not observed in A subunit-free preparations of the Stx1 B pentamer which competitively inhibited Stx2 B pentamer-mediated apoptosis. The pancaspase inhibitor, Z-VAD-fmk, prevented apoptosis in Ramos cells exposed to the Stx2 B subunit, Stx1 or Stx2. Brefeldin A, an inhibitor of the Golgi transport system, also prevented Stx2 B subunit-mediated apoptosis. These observations suggest that the Stx2 B subunit must be internalized, via Gb3-Cer receptors, to induce Ramos cell apoptosis. Moreover, unlike the two holotoxins, Stx2 B subunit-mediated apoptosis does not involve inhibition of protein biosynthesis. This study provides further insight into the pathogenic potential of this family of potent bacterial exotoxins.