bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dealing with the wicked issue of child poverty: Inter‐organizational networks as forums for collective debate and reflection
Authors: Jacquet Nicolas , Van Haute Dorien , De Corte Joris , Nisen Laurent , Vandenbroeck Michel , Roets Griet 
Published: March 2020

AbstractIn the international realm, inter‐organizational networking is perceived as a highly relevant instrument in social policy that enables welfare organizations to deal with “wicked issues.” In this article, we discuss the central empirical findings acquired from a recent qualitative research project that focuses on inter‐organizational networks that were formed at the local level to deal with the wicked issue of child poverty as a complex and multidimensional social problem. We explore how the network discussions about normative value orientations in four inter‐organizational networks evolve, and identify three central fields of tension that illustrate the complexity for local welfare actors in and across networks to create network strategies in dealing with child poverty: (a) selective versus universal provision, (b) conditional versus unconditional strategies, and (c) instrumental versus lifeworld‐oriented approaches. Our findings show that networks can function as valuable forums for collective debate and reflection, since different approaches and perspectives to tackle the problem of child poverty can be confronted with each other. Creating such a forum has the potential to challenge dominant conceptualizations and undesirable assumptions of complex social problems that are present in welfare practices and policies.
The Biphasic mRNA Expression Pattern of Bovine Interleukin-8 inPasteurella haemolyticaLipopolysaccharide-Stimulated Alveolar Macrophages Is Primarily due to Tumor Necrosis Factor Alpha
Authors: Lafleur Rhonda L. , Abrahamsen Mitchell S. , Maheswaran Samuel K. 
Published: March 2020

ABSTRACTPasteurella haemolyticaserotype 1 is the bacterial agent responsible for the pathophysiological events associated with bovine pneumonic pasteurellosis. Our previous studies support a role for the lipopolysaccharide (LPS) fromP. haemolyticain the induction of proinflammatory cytokines. One of the pathological hallmarks of bovine pneumonic pasteurellosis is an influx of neutrophils into the alveolar spaces. This pronounced influx suggests the local production of a chemotactic factor(s) such as interleukin-8 (IL-8). In the context of the lung, the alveolar macrophage appears to be the major producer of IL-8, a proinflammatory cytokine with potent neutrophil chemotactic activity. By using Northern blot analysis, we have examined the kinetics of IL-8 mRNA expression inP. haemolyticaLPS-stimulated bovine alveolar macrophages and found that 1 ng of LPS per ml induces maximal expression of IL-8 mRNA. The results also indicate a biphasic time course expression pattern in which IL-8 mRNA levels peak between 1 and 2 h in the first phase and between 16 and 24 h in the second phase (P< 0.01). In addition, monospecific polyclonal antibodies were used to demonstrate the role of tumor necrosis factor alpha (TNF-α) in the second phase of IL-8 mRNA expression. Our findings support a role forP. haemolyticaLPS and TNF-α in the induction of IL-8 from bovine alveolar macrophages.
A Peptide Domain on Gingipain R Which Confers Immunity against
Porphyromonas gingivalis
Infection in Mice
Authors: Genco Caroline Attardo , Odusanya Basil Michael , Potempa Jan , Mikolajczyk-Pawlinska Jowita , Travis James 
Published: March 2020

ABSTRACT

The cysteine proteinases referred to as gingipains R (gingipain R1 and gingipain R2) and gingipain K produced by
Porphyromonas gingivalis
are virulence factors of this periodontal pathogen which likely act by interrupting host defense mechanisms and by participating in the penetration and destruction of host connective tissue. To examine the effect of immunization with gingipains R on the ability of
P. gingivalis
to colonize and invade in the mouse chamber model, BALB/c mice were immunized intraperitoneally with the 95-kDa gingipain R1, the 50-kDa gingipain R2, or multiple antigenic peptide (MAP)-conjugated gingipain R-derived peptides and then challenged with
P. gingivalis
. Immunization of mice with the 95-kDa gingipain R1, the 50-kDa gingipain R2, or a peptide derived from the N-terminal sequence of the catalytic domain of gingipains R (peptide A) followed by challenge with
P. gingivalis
A7436 resulted in protection from
P. gingivalis
invasion. In contrast, immunization with peptides corresponding to either a sequence encompassing the catalytic cysteine residue of gingipains R (peptide B) or an identical sequence within the catalytic domains of gingipain R1 and gingipain K (peptide C), followed by challenge with
P. gingivalis
, did not protect animals, nor did immunization with a peptide corresponding to sequences within the adhesion/hemagglutinin domain of gingipain R1 (peptide D) which have been shown to be directly involved in the hemagglutinin activity of gingipain R1. However, the immunoglobulin G (IgG) titer obtained following immunization with peptide D was comparable to that obtained following immunization with the N-terminal peptide (peptide A). Competitive enzyme-linked immunosorbent assays, using either the 95-kDa gingipain R1 or gingipain K as the competing soluble antigen, indicated that 42 and 53% of the antibodies induced by immunization with heat-killed bacteria recognize gingipain R1 and gingipain K, respectively; however, even at very high concentrations, the 50-kDa gingipain R2 did not hinder IgG binding to
P. gingivalis
. These results indicate that antibodies directed to the amino-terminal region of the catalytic domain of gingipains R are capable of inducing a protective immune response against
P. gingivalis
infection in the mouse chamber model.
Hemolytically Active (Acylated) Alpha-Hemolysin Elicits Interleukin-1β (IL-1β) but Augments the Lethality ofEscherichia coliby an IL-1- and Tumor Necrosis Factor-Independent Mechanism
Authors: Gleason Thomas G. , Houlgrave C. Webster , May Addison K. , Crabtree Traves D. , Sawyer Robert G. , Denham Woody , Norman James G. , Pruett Timothy L. 
Published: March 2020

ABSTRACTMany pathogenicEscherichia coliproduce the toxin alpha-hemolysin (Hly), and lipopolysaccharide (LPS), interleukin-1 (IL-1), and tumor necrosis factor (TNF) have all been recognized as important effector molecules during infections by gram-negative organisms. Despite the characterization of many in vitro effects of hemolysin, no direct relationship has been established between hemolysin, LPS, proinflammatory cytokine production, andE. coli-induced mortality. Previously, we have shown in vivo that hemolysin elicits a distinct IL-1α spike by 4 h into a lethal hemolyticE. coliinfection. Using three transformedE. colistrains, WAF108, WAF270, and WAH540 (which produce no Hly [Hlynull], acylated Hly [Hlyactive], or nonacylated Hly [Hlyinactive], respectively), we sought to determine the specific roles of hemolysin acylation, LPS, IL-1, and TNF in mediating the lethality ofE. coliinfection in mice. WAF270 was 100% lethal in BALB/c, C3H/HeJ, and C57BL/6 mice; in mice pretreated with antibody to the type 1 IL-1 receptor; in type 1 IL-1 receptor-deficient mice; and in dual (type 1 IL-1 receptor-type 1 TNF receptor)-deficient mice at doses which were nonlethal (0%) with both WAF108 and WAH540. At lethal doses, WAF270 killed by 6 ± 2.3 h while WAF108 and WAH540 killed at 36 ± 9.4 and 36 ± 13.8 h, respectively. These differences in mortality were not due to IL-1 or TNF release, and the enhanced expression of LPS, which corresponded to Hly expression, was not likely the primary factor causing mortality. We demonstrate that bacterial fatty acid acylation of hemolysin is required in order for it to elicit IL-1 release by monocytes and to confer its virulence onE. coli.
Involvement of the
Haemophilus ducreyi gmhA
Gene Product in Lipooligosaccharide Expression and Virulence
Authors: Bauer Beth A. , Stevens Marla K. , Hansen Eric J. 
Published: March 2020

ABSTRACT

The lipooligosaccharide (LOS) present in the outer membrane of
Haemophilus ducreyi
is likely a virulence factor for this sexually transmitted pathogen. An open reading frame in
H. ducreyi
35000 was found to encode a predicted protein that had 87% identity with the protein product of the
gmhA
(
isn
) gene of
Haemophilus influenzae
. In
H. influenzae
type b, inactivation of the
gmhA
gene caused the synthesis of a significantly truncated LOS which possessed only lipid A and a single 2-keto-3-deoxyoctulosonic acid molecule (A. Preston, D. J. Maskell, A. Johnson, and E. R. Moxon, J. Bacteriol. 178:396–402, 1996). The
H. ducreyi gmhA
gene was able to complement a
gmhA
-deficient
Escherichia coli
strain, a result which confirmed the identity of this gene. When the
gmhA
gene of
H. ducreyi
was inactivated by insertion of a
cat
cartridge, the resultant
H. ducreyi gmhA
mutant, 35000.252, expressed a LOS that migrated much faster than wild-type LOS in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When the wild-type
H. ducreyi
strain and its isogenic
gmhA
mutant were used in the temperature-dependent rabbit model for dermal lesion production by
H. ducreyi
, the
gmhA
mutant was found to be substantially less virulent than the wild-type parent strain. The
H. ducreyi gmhA
gene was amplified by PCR from the
H. ducreyi
chromosome and cloned into the pLS88 vector. When the
H. ducreyi gmhA
gene was present in
trans
in
gmhA
mutant 35000.252, expression of the
gmhA
gene product restored the virulence of this mutant to wild-type levels. These results indicate that the
gmhA
gene product of
H. ducreyi
is essential for the expression of wild-type LOS by this pathogen.
Coiling Phagocytosis of Trypanosomatids and Fungal Cells
Authors: Rittig M. G. , Schröppel K. , Seack K.-H. , Sander U. , N’Diaye E.-N. , Maridonneau-Parini I. , Solbach W. , Bogdan C. 
Published: March 2020

ABSTRACT

Coiling phagocytosis has previously been studied only with the bacteria
Legionella pneumophila
and
Borrelia burgdorferi
, and the results were inconsistent. To learn more about this unconventional phagocytic mechanism, the uptake of various eukaryotic microorganisms by human monocytes, murine macrophages, and murine dendritic cells was investigated in vitro by video and electron microscopy. Unconventional phagocytosis of
Leishmania
spp. promastigotes,
Trypanosoma cruzi
trypomastigotes,
Candida albicans
hyphae, and zymosan particles from
Saccharomyces cerevisiae
differed in (i) morphology (rotating unilateral pseudopods with the trypanosomatids, overlapping bilateral pseudopods with the fungi), (ii) frequency (high with
Leishmania
; occasional with the fungi; rare with
T. cruzi
), (iii) duration (rapid with zymosan; moderate with the trypanosomatids; slow with
C. albicans
), (iv) localization along the promastigotes (flagellum of
Leishmania major
and
L. aethiopica
; flagellum or posterior pole of
L. donovani
), and (v) dependence on complement (strong with
L. major
and
L. donovani
; moderate with the fungi; none with
L. aethiopica
). All of these various types of unconventional phagocytosis gave rise to similar pseudopod stacks which eventually transformed to a regular phagosome. Further video microscopic studies with
L. major
provided evidence for a cytosolic localization, synchronized replication, and exocytic release of the parasites, extending traditional concepts about leishmanial infection of host cells. It is concluded that coiling phagocytosis comprises phenotypically similar consequences of various disturbances in conventional phagocytosis rather than representing a single separate mechanism.
An Essential Role for Interleukin-5 and Eosinophils in Helminth-Induced Airway Hyperresponsiveness
Authors: Hall Laurie R. , Mehlotra Rajeev K. , Higgins Alan W. , Haxhiu Musa A. , Pearlman Eric 
Published: March 2020

ABSTRACTInfection with the parasitic helminthBrugia malayican result in development of a severe asthmatic response termed tropical pulmonary eosinophilia. This disease, thought to result from a host inflammatory response to blood parasites which become trapped in the lung microvasculature, is characterized by a profound eosinophilic infiltration into the lungs. Recruitment of eosinophils also correlates with the development of airway hyperresponsiveness (AHR) to cholinergic agonists and severe asthmatic symptoms. Our studies examined the role of interleukin-5 (IL-5) in helminth-induced pulmonary eosinophilia and AHR. C57BL/6 mice immunized with killedB. malayimicrofilariae and challenged intravenously with live microfilariae exhibit many of the characteristics of human disease, including peripheral and pulmonary eosinophilia. Cells recovered by bronchoalveolar lavage of sensitized mice consisted of 3.8% eosinophils on day 1 postchallenge and 84% on day 10. Extracellular major basic protein was present on the surface of airway epithelial cells as early as day 1 and continued to be evident after 8 days, indicating sustained activation and degranulation of eosinophils in the lung. These histologic changes correlated with the development of AHR to carbachol. In contrast to immunocompetent mice, immunization and challenge withB. malayiin IL-5−/−mice did not induce peripheral or pulmonary eosinophilia, and these mice failed to show AHR in response to cholinergic agonists. Taken together, these data indicate that IL-5 and eosinophils are required for the induction of AHR by filarial helminths.
Induction of Fibrinogen Expression in the Lung Epithelium duringPneumocystis cariniiPneumonia
Authors: Simpson-Haidaris Patricia J. , Courtney Mary-Anne , Wright Terry W. , Goss Rachel , Harmsen Allen , Gigliotti Francis 
Published: March 2020

ABSTRACTPneumocystis cariniiis an important pulmonary pathogen responsible for morbidity and mortality in patients with AIDS. The acute-phase response (APR), the primary mechanism used by the body to restore homeostasis following infection, is characterized by increased levels of circulating fibrinogen (FBG). Although the liver is the primary site of increased FBG synthesis during the APR, we unexpectedly discovered that FBG is synthesized and secreted by lung alveolar epithelial cells in vitro during an inflammatory stimulus. Therefore, we sought to determine whether lung epithelial cells produce FBG in vivo using animal models ofP. cariniipneumonia (PCP). Inflammation was noted by an influx of macrophages toP. carinii-infected alveoli. Northern hybridization revealed that γ-FBG mRNA increased two- to fivefold inP. carinii-infected lung tissue, while RNA in situ hybridization demonstrated increased levels of γ-FBG mRNA in the lung epithelium. Immunoelectron microscopy detected lung epithelial cell-specific production of FBG, suggesting induction of a localized inflammatory response resembling the APR. A systemic APR was confirmed by a two- to fivefold upregulation of the levels of hepatic γ-FBG mRNA in animals with PCP, resulting in a corresponding increase in levels of FBG in plasma. Furthermore, immunoelectron microscopy revealed the presence of FBG at the junction of cell membranes of trophic forms ofP. cariniiorganisms aggregated along the alveolar epithelium. These results implicate FBG in the pathogenesis of PCP in a manner similar to that of the adhesive glycoproteins fibronectin and vitronectin, which are known to participate in intra-alveolar aggregation of organisms and adherence ofP. cariniito the lung epithelium.
Actinobacillus actinomycetemcomitansLeukotoxin Induces Apoptosis in HL-60 Cells
Authors: Korostoff Jonathan , Wang Jian Fei , Kieba Irene , Miller Mark , Shenker Bruce J. , Lally Edward T. 
Published: March 2020

ABSTRACTActinobacillus actinomycetemcomitansleukotoxin (Ltx) is a member of the repeats-in-toxin (RTX) family of pore-forming toxins and kills human immune cells. Currently, it remains unclear whether toxin-mediated killing of target cells involves the induction of necrosis or apoptosis. Therefore, the goal of this investigation was to determine whether Ltx is capable of causing apoptotic cell death in toxin-sensitive promyelocytic HL-60 cells. Multiparameter flow cytometric analysis of toxin-treated cells stained with Hoechst 33258 (or 33342) and 7-aminoactinomycin D allowed us to identify four populations: viable cells, early apoptotic cells, late apoptotic and/or secondarily necrotic cells, and a final population that was composed of cellular debris. Compared with control cells, HL-60 cells treated with Ltx exhibited a gradual decrease in forward light scatter with a coincident increase in side light scatter, indicative of a decrease in cell size and organelle condensation, respectively. Additional experiments demonstrated that Ltx-treated cells showed evidence of internucleosomal DNA fragmentation and phosphatidylserine translocation. The results of our studies clearly demonstrate that Ltx can kill HL-60 cells by inducing apoptosis. We hypothesize that elimination of acute inflammatory cells via this mechanism plays a critical role in the pathogenesis of diseases caused byA. actinomycetemeomitans.
The
Helicobacter pylori
UreI Protein Is Not Involved in Urease Activity but Is Essential for Bacterial Survival In Vivo
Authors: Skouloubris Stéphane , Thiberge Jean-Michel , Labigne Agnès , De Reuse Hilde 
Published: March 2020

ABSTRACT

We produced defined isogenic
Helicobacter pylori ureI
mutants to investigate the function of UreI, the product of one of the genes of the urease cluster. The insertion of a
cat
cassette had a strong polar effect on the expression of the downstream urease genes, resulting in very weak urease activity. Urease activity, measured in vitro, was normal in a strain in which
ureI
was almost completely deleted and replaced with a nonpolar cassette. In contrast to previous reports, we thus found that the product of
ureI
was not necessary for the synthesis of active urease. Experiments with the mouse-adapted
H. pylori
SS1 strain carrying the nonpolar
ureI
deletion showed that UreI is essential for
H. pylori
survival in vivo and/or colonization of the mouse stomach. The replacement of
ureI
with the nonpolar cassette strongly reduced
H. pylori
survival in acidic conditions (1-h incubation in phosphate-buffered saline solution at pH 2.2) in the presence of 10 mM urea. UreI is predicted to be an integral membrane protein and may therefore be involved in a transport process essential for
H. pylori
survival in vivo.
Isolation of
Enterococcus faecalis
Clinical Isolates That Efficiently Adhere to Human Bladder Carcinoma T24 Cells and Inhibition of Adhesion by Fibronectin and Trypsin Treatment
Authors: Shiono Akihiko , Ike Yasuyoshi 
Published: March 2020

ABSTRACT

The adherence of
Enterococcus faecalis
strains to human T24 cells was examined by scanning electron microscopy. Five highly adhesive strains were identified from 30 strains isolated from the urine of patients with urinary tract infections. No efficiently adhesive strains were found among the 30 strains isolated from the feces of healthy students. The five isolated strains also adhered efficiently to human bladder epithelial cells. Analysis of restriction endonuclease-digested plasmid DNAs and chromosome DNAs showed that the five strains were different strains isolated from different patients. The adhesiveness of these strains was inhibited by treatment with fibronectin or trypsin, implying that a specific protein (adhesin) on the bacterial cell surface mediates adherence to fibronectin on the host cell surfaces, and the adhesin differs from the reported adhesins.
In Vivo Expression and Immunoadjuvancy of a Mutant of Heat-Labile Enterotoxin ofEscherichia coliin Vaccine and Vector Strains ofVibrio cholerae
Authors: Ryan Edward T. , Crean Thomas I. , John Manohar , Butterton Joan R. , Clements John D. , Calderwood Stephen B. 
Published: March 2020

ABSTRACTVibrio choleraesecretes cholera toxin (CT) and the closely related heat-labile enterotoxin (LT) ofEscherichia coli, the latter when expressed inV. cholerae. Both toxins are also potent immunoadjuvants. Mutant LT molecules that retain immunoadjuvant properties while possessing markedly diminished enterotoxic activities when expressed byE. colihave been developed. One such mutant LT molecule has the substitution of a glycine residue for arginine-192 [LT(R192G)]. Live attenuated strains ofV. choleraethat have been used both asV. choleraevaccines and as vectors for inducing mucosal and systemic immune responses directed against expressed heterologous antigens have been developed. In order to ascertain whether LT(R192G)can act as an immunoadjuvant when expressed in vivo byV. cholerae, we introduced a plasmid (pCS95) expressing this molecule into three vaccine strains ofV. cholerae, Peru2, ETR3, and JRB14; the latter two strains contain genes encoding different heterologous antigens in the chromosome of the vaccine vectors. We found that LT(R192G)was expressed from pCS95 in vitro by bothE. coliandV. choleraestrains but that LT(R192G)was detectable in the supernatant fraction ofV. choleraecultures only. In order to assess potential immunoadjuvanticity, groups of germfree mice were inoculated with the threeV. choleraevaccine strains alone and compared to groups inoculated with theV. choleraevaccine strains supplemented with purified CT as an oral immunoadjuvant orV. choleraevaccine strains expressing LT(R192G)from pCS95. We found that mice continued to pass stool containingV. choleraestrains with pCS95 for at least 4 days after oral inoculation, the last day evaluated. We found that inoculation withV. choleraevaccine strains containing pCS95 resulted in anti-LT(R192G)immune responses, confirming in vivo expression. We were unable to detect immune responses directed against the heterologous antigens expressed at low levels in any group of animals, including animals that received purified CT as an immunoadjuvant. We were, however, able to measure increased vibriocidal immune responses against vaccine strains in animals that receivedV. choleraevaccine strains expressing LT(R192G)from pCS95 compared to the responses in animals that receivedV. choleraevaccine strains alone. These results demonstrate that mutant LT molecules can be expressed in vivo by attenuated vaccine strains ofV. choleraeand that such expression can result in an immunoadjuvant effect.
The
rgg
Gene of
Streptococcus pyogenes
NZ131 Positively Influences Extracellular SPE B Production
Authors: Chaussee Michael S. , Ajdic Dragana , Ferretti Joseph J. 
Published: March 2020

ABSTRACT

Streptococcus pyogenes
produces several extracellular proteins, including streptococcal erythrogenic toxin B (SPE B), also known as streptococcal pyrogenic exotoxin B and streptococcal proteinase. Several reports suggest that SPE B contributes to the virulence associated with
S. pyogenes
; however, little is known about its regulation. Nucleotide sequence data revealed the presence, upstream of the
speB
gene, of a gene, designated
rgg
, that was predicted to encode a polypeptide similar to previously described positive regulatory factors. The putative Rgg polypeptide of
S. pyogenes
NZ131 consisted of 280 amino acids and had a predicted molecular weight of 33,246. To assess the potential role of Rgg in the production of SPE B, the
rgg
gene was insertionally inactivated in
S. pyogenes
NZ131, which resulted in markedly decreased SPE B production, as determined both by immunoblotting and caseinolytic activity on agar plates. However, the production of other extracellular products, including streptolysin O, streptokinase, and DNase, was not affected. Complementation of the
rgg
mutant with an intact
rgg
gene copy in
S. pyogenes
NZ131 could restore SPE B production and confirmed that the
rgg
gene product is involved in the production of SPE B.