bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a Glycoprotein Produced by Enterotoxigenic
Escherichia coli
Authors: Lindenthal Christoph , Elsinghorst Eric A. 
Published: December 2019

ABSTRACT

Enterotoxigenic
Escherichia coli
(ETEC) strain H10407 is capable of invading epithelial cell lines derived from the human ileocecum and colon in vitro. Two separate chromosomally encoded invasion loci (
tia
and
tib
) have been cloned from this strain. These loci direct nonadherent and noninvasive laboratory strains of
E. coli
to adhere to and invade cultured human intestinal epithelial cells. The
tib
locus directs the synthesis of TibA, a 104-kDa outer membrane protein that is directly correlated with the adherence and invasion phenotypes. TibA is synthesized as a 100-kDa precursor (preTibA) that must be modified for biological activity. Outer membranes of recombinant
E. coli
expressing TibA or preTibA were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted to nitrocellulose. The presence of glycoproteins was detected by oxidization of carbohydrates with periodate and labeling with hydrazide-conjugated digoxigenin. Only TibA could be detected as a glycoprotein. Complementation experiments with
tib
deletion mutants of ETEC strain H10407 demonstrate that the TibA glycoprotein is expressed in H10407, that the entire
tib
locus is required for TibA synthesis, and that TibA is the only glycoprotein produced by H10407. Protease treatment of intact H10407 cells removes the carbohydrates on TibA, suggesting that they are surface exposed. TibA shows homology with AIDA-I from diffuse-adhering
E. coli
and with pertactin precursor from
Bordetella pertussis
. Both pertactin and AIDA-I are members of the autotransporter family of outer membrane proteins and are afimbrial adhesins that play an important role in the virulence of these organisms. Analysis of the predicted TibA amino acid sequence indicates that TibA is also an autotransporter. Analysis of the
tib
locus DNA sequence revealed an open reading frame with similarity to RfaQ, a glycosyltransferase. The product of this
tib
locus open reading frame is proposed to be responsible for TibA modification. These results suggest that TibA glycoprotein acts as an adhesin that may participate in the disease process.
Purification and Properties of Proline-Rich Antimicrobial Peptides from Sheep and Goat Leukocytes
Authors: Shamova Olga , Brogden Kim A. , Zhao Chengquan , Nguyen Tung , Kokryakov Vladimir N. , Lehrer Robert I. 
Published: December 2019

ABSTRACTWe purified three proline-rich antimicrobial peptides from elastase-treated extracts of sheep and goat leukocytes and subjected two of them, OaBac5α and ChBac5, to detailed analysis. OaBac5α and ChBac5 were homologous to each other and to bovine Bac5. Both exhibited potent, broad-spectrum antimicrobial activity under low-concentration salt conditions. While the peptides remained active againstEscherichia coli,Pseudomonas aeruginosa,Bacillus subtilis, andListeria monocytogenesin 100 mM NaCl, they lost activity againstStaphylococcus aureusandCandida albicansunder these conditions. ChBac5 was shown to bind lipopolysaccharide, a property that could enhance its ability to kill gram-negative bacteria. Proline-rich Bac5 peptides are highly conserved in ruminants and may contribute significantly to their innate host defense mechanisms.
Expression of Fas and Fas Ligand on Mouse Renal Tubular Epithelial Cells in the Generalized Shwartzman Reaction and Its Relationship to Apoptosis
Authors: Koide Naoki , Narita Kayo , Kato Yutaka , Sugiyama Tsuyoshi , Chakravortty Dipshikha , Morikawa Akiko , Yoshida Tomoaki , Yokochi Takashi 
Published: December 2019

ABSTRACTPreviously we reported that the consecutive injection of lipopolysaccharide (LPS) into LPS-sensitized mice for the generalized Shwartzman reaction (GSR) appeared to induce the injury of renal tubular epithelial cells via apoptosis. The aim of this study was to characterize the mechanism of renal tubular epithelial cell injury in GSR. The expression of Fas and Fas ligand was immunohistochemically detected on renal tubular epithelial cells from GSR-induced mice, although neither Fas nor Fas ligand was found in cells from untreated control mice or in cells from mice receiving a single injection of LPS. GSR-induced renal tubular epithelial cell injury was produced in neither Fas-negative MRL-lpr/lprmice nor Fas ligand-negative MRL-gld/gldmice. The administration of anti-gamma interferon antibody together with a preparative injection of LPS prevented the expression of Fas and Fas ligand and the apoptosis of renal tubular epithelial cells. A provocative injection of tumor necrosis factor alpha into LPS-sensitized mice augmented Fas and Fas ligand expression and the apoptosis of renal tubular epithelial cells. The administration of tumor necrosis factor alpha to interleukin-12-sensitized mice resulted in Fas and Fas ligand expression and the apoptosis. Sensitization with interleukin-12 together with anti-gamma interferon antibody did not cause the apoptosis of renal tubular epithelial cells. It was suggested that the Fas/Fas ligand system probably plays a critical role in the development of renal tubular epithelial cell injury through apoptotic cell death.
Comparative Analysis of
Legionella pneumophila
and
Legionella micdadei
Virulence Traits
Authors: Joshi Amrita D. , Swanson Michele S. 
Published: December 2019

ABSTRACT

While the majority of Legionnaire’s disease has been attributed to
Legionella pneumophila
,
Legionella micdadei
can cause a similar infection in immunocompromised people. Consistent with its epidemiological profile, the growth of
L. micdadei
in cultured macrophages is less robust than that of
L. pneumophila
. To identify those features of the
Legionella
spp. which are correlated to efficient growth in macrophages, two approaches were taken. First, a phenotypic analysis compared four clinical isolates of
L. micdadei
to one well-characterized strain of
L. pneumophila
. Seven traits previously correlated with the virulence of
L. pneumophila
were evaluated: infection and replication in cultured macrophages, evasion of phagosome-lysosome fusion, contact-dependent cytotoxicity, sodium sensitivity, osmotic resistance, and conjugal DNA transfer. By nearly every measure,
L. micdadei
appeared less virulent than
L. pneumophila
. The surprising exception was
L. micdadei
31B, which evaded lysosomes and replicated in macrophages as efficiently as
L. pneumophila
, despite lacking both contact-dependent cytopathicity and regulated sodium sensitivity. Second, in an attempt to identify virulence factors genetically, an
L. pneumophila
genomic library was screened for clones which conferred robust intracellular growth on
L. micdadei
. No such loci were isolated, consistent with the multiple phenotypic differences observed for the two species. Apparently,
L. pneumophila
and
L. micdadei
use distinct strategies to colonize alveolar macrophages, causing Legionnaire’s disease.
Myeloperoxidase Exerts Microbicidal Activity againstMycobacterium tuberculosis
Authors: Borelli Violetta , Banfi Elena , Perrotta Maria Giovanna , Zabucchi Giuliano 
Published: December 2019

ABSTRACTWe investigated the antimycobacterial role of myeloperoxidase (MPO), one of the most abundant granule proteins in human neutrophils. Our data indicate that purified MPO, in the presence of hydrogen peroxide, exerts a consistent killing activity againstMycobacterium tuberculosisH37Rv and against a clinical isolate. The activity is time and dose dependent and requires the presence of chloride ions in the assay medium.
Infection of Primary Human Bronchial Epithelial Cells by
Haemophilus influenzae
: Macropinocytosis as a Mechanism of Airway Epithelial Cell Entry
Authors: Ketterer Margaret R. , Shao Jian Q. , Hornick Douglas B. , Buscher Ben , Bandi Venkata K. , Apicella Michael A. 
Published: December 2019

ABSTRACT

Nontypeable
Haemophilus influenzae
is an exclusive human pathogen which infects the respiratory epithelium. We have initiated studies to explore the interaction of the nontypeable
H. influenzae
strain 2019 with primary human airway epithelial cells by electron and confocal microscopy. Primary human airway cell cultures were established as monolayers on glass collagen-coated coverslips or on semipermeable membranes at an air-fluid interface. Scanning electron microscopy indicated that bacteria adhered to nonciliated cells in the population. The surface of infected cells showed evidence of cytoskeletal rearrangements manifested by microvilli and lamellipodia extending toward and engaging bacteria. Confocal microscopic analysis demonstrated that infection induced actin polymerization with an increase in cortical actin as well as evidence of actin strands around the bacteria. Transmission electron microscopic analysis showed lamellipodia and microvilli surrounding organisms, as well as organisms adherent to the cell surface. These studies also demonstrated the presence of bacteria within vacuoles inside of airway cells. Confocal microscopic studies with Texas red-labeled dextran (molecular weight, 70,000) indicated that
H. influenzae
cells were entering cells by the process of macropinocytosis. These studies indicate that nontypeable
H. influenzae
can initiate cytoskeletal rearrangement within human airway epithelium, resulting in internalization of the bacteria within nonciliated human airway epithelial cells by the process of macropinocytosis.
Differences in the Concentrations of Small, Anionic, Antimicrobial Peptides in Bronchoalveolar Lavage Fluid and in Respiratory Epithelia of Patients with and without Cystic Fibrosis
Authors: Brogden Kim A. , Ackermann Mark R. , McCray Paul B. , Huttner Kenneth M. 
Published: December 2019

ABSTRACT

Affinity-purified rabbit polyclonal (PAB96-1) and mouse monoclonal (1G9-1C2) antibodies to synthetic H-DDDDDDD-OH, an antimicrobial anionic peptide (AP) originally isolated from ovine pulmonary surfactant, were prepared and used to assess the concentrations of AP-like molecules in human respiratory tract samples. In bronchoalveolar lavage fluids, concentrations of AP-like molecules measured by enzyme-linked immunosorbent assay were significantly lower in 13 patients with cystic fibrosis (CF) (mean ± standard deviation [SD], 0.78 ± 0.46 mM) than in 34 patients without CF (1.30 ± 0.66 mM) (
P
= 0.01). In pulmonary tissues of three patients without CF, very little antigen was stained in the apical cytoplasm of the bronchial and bronchiolar epithelium yet robust staining was seen in the alveolar epithelium. In pulmonary tissues of three patients with CF, robust staining of antigen was seen in the apical cytoplasm of the bronchial and bronchiolar epithelium yet no staining was seen in the alveolar epithelium. These results show that AP-like molecules are present in healthy human respiratory tract samples and differ in concentration and location of expression in patients with and without CF.
Streptococcal Pyrogenic Exotoxin F (SpeF) Causes Permeabilization of Lung Blood Vessels
Authors: Matsumoto Masakado , Ishikawa Naohisa , Saito Makoto , Shibayama Keigo , Horii Toshinobu , Sato Kumiko , Ohta Michio 
Published: December 2019

ABSTRACT

Acute respiration distress syndrome (ARDS) is a typical complication in toxic shock-like syndrome (TSLS) caused by
Streptococcus pyogenes
. An isolated perfused rat lung model was used to identify the causative agent of ARDS in TSLS in this study. Some crude preparations separated from the culture supernatants of
S. pyogenes
isolates caused rapid increases in the weight of perfused lungs, indicating vascular permeabilization. Six samples from M type 1 and 3 isolates from TSLS and pharyngitis patients showed strong permeabilization activity, whereas preparations from isolates of other M types (although the number of isolates examined was limited) were negative. The active substance was purified to a single band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis using various columns, and the N-terminal amino acid sequence was determined. The resultant sequence of eight amino acids was identical to SpeF (mitogenic factor). Moreover, the vascular permeabilization activity of the purified band was abolished with anti-SpeF antiserum prepared by immunizing with the purified SpeF. This activity was also neutralized by the antiserum prepared by immunizing with a synthetic peptide derived from the published SpeF sequence. These results suggested that streptococcal SpeF is a major cause of permeabilization of lung blood vessels and sufficient for the pathogenesis of ARDS under the conditions of TSLS caused by
S. pyogenes
.
Group A Streptococcus Induces Apoptosis in Human Epithelial Cells
Authors: Tsai Pei-Jane , Lin Yee-Shin , Kuo Chih-Feng , Lei Huan-Yao , Wu Jiunn-Jong 
Published: December 2019

ABSTRACTInternalization of group A streptococcus (GAS) by epithelial cells may have a role in causing invasive diseases. The purpose of this study was to examine the fate of GAS-infected epithelial cells. GAS has the ability to invade A-549 and HEp-2 cells. Both A-549 and HEp-2 cells were killed by infection with GAS. Epithelial cell death mediated by GAS was at least in part through apoptosis, as shown by changes in cellular morphology, DNA fragmentation laddering, and propidium iodide staining for hypodiploid cells. A total of 20% of A-549 cells and 11 to 13% of HEp-2 cells underwent apoptosis after 20 h of GAS infection, whereas only 1 to 2% of these cells exhibited spontaneous apoptosis. We further examined whether streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease produced by GAS, was involved in the apoptosis of epithelial cells. ThespeBisogenic mutants had less ability to induce cell death than wild-type strains. When A-549 cells were cocultured with the mutant and SPE B for 2 h, the percentage of apoptotic cells did not increase although the number of intracellular bacteria increased to the level of wild-type strains. In addition, apoptosis was blocked by cytochalasin D treatment, which interfered with cytoskeleton function. The caspase inhibitors Z-VAD.FMK, Ac-YVAD.CMK, and Ac-DEVD.FMK inhibited GAS-induced apoptosis. These results demonstrate for the first time that GAS induces apoptosis of epithelial cells and internalization is required for apoptosis. The caspase pathway is involved in GAS-induced apoptosis, and the expression of SPE B in the cells enhances apoptosis.
Protective Role for Interleukin-5 during ChronicToxoplasma gondiiInfection
Authors: Zhang Yin , Denkers Eric Y. 
Published: December 2019

ABSTRACTTo investigate the role of interleukin-5 (IL-5) duringToxoplasma gondiiinfection, IL-5 knockout (KO) mice and C57BL/6 control mice were infected intraperitoneally with ME49 cysts and the course of infection was monitored. The mortality rate during chronic infection was significantly greater in IL-5-deficient animals, and consistent with this finding, the KO mice harbored a greater number of brain cysts and tachyzoites than did their wild-type counterparts. Although the IL-5 KO animals did not succumb until late during infection, increased susceptibility, as measured by accelerated weight loss, was detectable during the acute stages of infection. The amounts of total immunoglobulin (Ig), IgM, and IgG2b were comparable in both strains, while the amount of IgG1 was much smaller in IL-5 KO mice. Spleen cell production of IL-12 in response toT. gondiiantigen was approximately threefold lower in the KO strain, and this decrease correlated with a selective loss of B lymphocytes during culture. A link between the presence of B cells and augmented IL-12 production was established by the finding that after removal of B cells with monoclonal antibody and complement, wild-type- and KO-derived cells produced equivalent levels of IL-12 in response toT. gondiiantigen. These results demonstrate a protective role of IL-5 againstT. gondiiinfection and suggest that IL-5 may play a role in the production of IL-12.
Intracellular Growth inAcanthamoeba castellaniiAffects Monocyte Entry Mechanisms and Enhances Virulence ofLegionella pneumophila
Authors: Cirillo Jeffrey D. , Cirillo Suat L. G. , Yan Ling , Bermudez Luiz E. , Falkow Stanley , Tompkins Lucy S. 
Published: December 2019

ABSTRACTSinceLegionella pneumophilais an intracellular pathogen, entry into and replication within host cells are thought to be critical to its ability to cause disease.L. pneumophilagrown in one of its environmental hosts,Acanthamoeba castellanii, is phenotypically different fromL. pneumophilagrown on standard laboratory medium (BCYE agar). Although amoeba-grownL. pneumophiladisplays enhanced entry into monocytes compared to BCYE-grown bacteria, the mechanisms of entry used and the effects on virulence have not been examined. To explore whether amoeba-grownL. pneumophiladiffers from BCYE-grownL. pneumophilain these characteristics, we examined entry into monocytes, replication in activated macrophages, and virulence in mice. Entry of amoeba-grownL. pneumophilainto monocytes occurred more frequently by coiling phagocytosis, was less affected by complement opsonization, and was less sensitive to microtubule and microfilament inhibitors than was entry of BCYE-grown bacteria. In addition, amoeba-grownL. pneumophiladisplays increased replication in monocytes and is more virulent in A/J, C57BL/6 Beige, and C57BL/6 mice. These data demonstrate for the first time that the intra-amoebal growth environment affects the entry mechanisms and virulence ofL. pneumophila.
Molecular and Idiotypic Analyses of the Antibody Response toCryptococcus neoformansGlucuronoxylomannan-Protein Conjugate Vaccine in Autoimmune and Nonautoimmune Mice
Authors: Nussbaum Gabriel , Anandasabapathy Sharmila , Mukherjee Jean , Fan Manxia , Casadevall Arturo , Scharff Matthew D. 
Published: December 2019

ABSTRACTThe antibody response toCryptococcus neoformanscapsular glucuronoxylomannan (GXM) in BALB/c mice frequently expresses the 2H1 idiotype (Id) and is restricted in variable gene usage. This study examined the immunogenicity of GXM-protein conjugates, V (variable)-region usage, and 2H1 Id expression in seven mouse strains: BALB/c, C57BL/6, A/J, C3H, NZB, NZW, and (NZB × NZW)F1(NZB/W). All mouse strains responded to vaccination with GXM conjugated to tetanus toxoid (TT), the relative magnitude of the antibody response being BALB/c ∼ C3H > C57BL/6 ∼ NZB ∼ NZW ∼ NZB/W > A/J. Analysis of serum antibody responses to GXM with polyclonal and monoclonal antibodies to the 2H1 Id revealed significant inter- and intrastrain differences in idiotype expression. Thirteen monoclonal antibodies (MAbs) (two immunoglobulin M [IgM], three IgG3, one IgG1, three IgG2a, two IgG2b, and two IgA) to GXM were generated from one NZB/W mouse and one C3H/He mouse. The MAbs from the NZB/W mouse were all 2H1 Id positive (Id+) and structurally similar to those previously generated in BALB/c mice, including the usage of a VHfrom the 7183 family and Vκ5.1. Administration of both 2H1 Id+and Id−MAbs from NZB/W and C3H/H3 mice prolonged survival in a mouse model of cryptococcosis. Our results demonstrate (i) that V-region restriction as indicated by the 2H1 Id is a feature of both primary and secondary responses of several mouse strains; and (ii) that there is conservation of V-region usage and length of the third complementarity-determining region in antibodies from three mouse strains. The results suggest that V-region restriction is a result of antibody structural requirements necessary for binding an immunodominant antigen in GXM.
Analysis of Antigenic Structure and Human Immune Response to Outer Membrane Protein CD of
Moraxella catarrhalis
Authors: Murphy Timothy F. , Kirkham Charmaine , DeNardin Ernesto , Sethi Sanjay 
Published: December 2019

ABSTRACT

Moraxella catarrhalis
is an important cause of otitis media in children and lower respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Outer membrane protein CD (OMP CD) is a 45-kDa protein which is a potential vaccine antigen to prevent infections caused by
M. catarrhalis
. Eight monoclonal antibodies were used to study the antigenic structure of the OMP CD molecule by assaying recombinant peptides corresponding to the sequence of the protein. This approach identified two surface-exposed epitopes, including one near the amino terminus (amino acids 25 to 44) and one in the central region of the molecule (amino acids 261 to 331). Assays with serum and sputum supernatants of adults with COPD revealed variable levels of antibodies to OMP CD among individuals. To determine which portions of the OMP CD molecule were recognized by human antibodies, three human serum samples were studied with six recombinant peptides which span the sequence of OMP CD. All three sera contained immunoglobulin G antibodies which recognized exclusively the peptide corresponding to amino acids 203 to 260 by immunoblot assay. Adsorption experiments with whole bacteria established that some of the human antibodies are directed at surface-exposed epitopes on OMP CD. We conclude that OMP CD is a highly conserved molecule which contains at least two separate epitopes which are exposed on the bacterial surface. While individual adults with COPD show variability in the immune response to OMP CD, a specific region of the OMP CD molecule (amino acids 203 to 260) is important as a target of the human immune response.
Pseudomonas aeruginosaExoenzyme S Stimulates Murine Lymphocyte Proliferation In Vitro
Authors: Barclay Neil G. , Spurrell Jason C. L. , Bruno Tony F. , Storey Douglas G. , Woods Donald E. , Mody Christopher H. 
Published: December 2019

ABSTRACTThe exuberant immunoinflammatory response that is associated withPseudomonas aeruginosainfection is the major source of the morbidity and mortality in cystic fibrosis (CF) patients. Previous studies have established that an exoproduct ofP. aeruginosa(exoenzyme S) is a mitogen for human T lymphocytes and activates a larger percentage of T cells than most superantigens, which may contribute to the immunoinflammatory response. An animal model would facilitate studies of the pathophysiologic consequences of this activation. As a first step toward developing an animal model, the murine lymphocyte response to exoenzyme S was examined. When stimulated with exoenzyme S, splenocytes isolated from naive mice entered S phase and proliferated. The optimum response occurred after 2 to 3 days in culture, at 4 × 105cells per well and 5.0 μg of exoenzyme S per ml. The response was not due to lipopolysaccharide, sinceRhodobacter sphaeroideslipid A antagonist did not block the response. Other preparations of exoenzyme S stimulated lymphocyte proliferation, since the response to recombinant exoenzyme S (rHisExo S) cloned from strain 388 was similar to the response to exoenzyme S from strain DG1. There was evidence that genetic variability influenced the response, since A/J, CBA/J, and C57BL/6 mice were high responders and BALB/cJ mice were low responders following stimulation with exoenzyme S. Both splenic T and B lymphocytes entered the cell cycle in response to exoenzyme S. Thus, murine lymphocytes, like human lymphocytes, respond toP. aeruginosaexoenzyme S, which supports the development of a murine model that may facilitate our understanding of the role that exoenzyme S plays in the pathogenesis ofP. aeruginosainfections in CF patients.