bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Characterization of Major Histocompatibility Complex Class I (B‐F) mRNA Variants from Chickens Differing in Resistance to Marek's Disease
Authors: Dalgaard T. S. , Vitved L. , Skjødt K. , Thomsen B. , Labouriau R. , Jensen K. H. , Juul‐Madsen H. R. 
Published: September 2005

AbstractIn this study, the relative distributions of two alternatively polyadenylated chicken major histocompatibility complex (MHC) mRNA isoforms of approximately 1.5 and 1.9 kb were analysed in spleen cells from chickens homozygous for the MHC haplotypes B21 and B19v1 as well as in heterozygous B19v1/B21 birds. Both isoforms are likely to encode classical MHC class I (B‐F) alpha chains. The B19v1 and B21 MHC haplotypes confer different levels of protection against Marek's disease (MD), which is caused by infection with MD virus (MDV). In spleen cells, MD‐resistant B21 birds were shown to have the highest percentage of the 1.5 kb variant relative to the total MHC class I expression, MD‐susceptible B19v1 birds the lowest and B19v1/B21 birds an intermediate percentage. Infection of 4‐week‐old chickens with the GA strain of MDV was shown to cause a significant increase in the relative amount of 1.5 kb transcripts in B21 birds 32 days postinfection (dpi). Alternatively polyadenylated mRNA isoforms may encode identical proteins, but differences in the 3′ untranslated region (UTR) can influence polyadenylation, mRNA stability, intracellular localization and translation efficiency. It was shown that the increased 1.5 kb percentage in B21 birds 32 days postinfection may be a result of a change in the choice of poly(A) site rather than a locus‐specific upregulated transcription of the BF1 gene that preferentially expresses the 1.5 kb variant. Furthermore, the 3′ end of the 1.5 kb mRNA variants deriving from B19v1 and B21 chickens was characterized by Rapid Amplification of cDNA Ends (RACE) and sequencing. No potentially functional elements were identified in the 3′ UTR of the RACE products corresponding to this short isoform. However, variation in polyadenylation site was observed between the BF1 and BF2 mRNA transcripts and alternative splicing‐out of the sequence (exon 7) encoding the second segment of the cytoplasmic part of the mature BF2*19 molecules. This alternative exon 7 splice variant was also detected in other MD‐susceptible haplotypes, but not in the MD‐resistant B21 and B21‐like haplotypes, suggesting a potential role of exon 7 in MHC‐related MD resistance.
Development of Early PCLP1‐Expressing Haematopoietic Cells within the Avian Dorsal Aorta
Authors: Suonpää P. , Kohonen P. , Koskela K. , Koskiniemi H. , Salminen‐Mankonen H. , Lassila O. 
Published: September 2005

AbstractThe first haematopoietic stem cells (HSC) develop in the dorsal aorta as haematopoietic intra‐aortic clusters (HIAC). To evaluate the initial steps of definitive haematopoiesis, we have studied the emergence and the expression profile of podocalyxin‐like protein 1 (PCLP1)‐expressing cells in early chick embryos. Here we demonstrate that at embryonic day 2 (E2), the PCLP1+ cells are present in the splanchnic mesoderm and in the ventral lining of the paired dorsal aorta. Following aortic fusion at E3, the PCLP1‐expressing cells are exclusively found in the aortic floor and as the development proceeds, both the haematopoietic clusters and the aortic endothelial cells express PCLP1. In parallel with the early PCLP1 expression, bone morphogenetic protein 4 (BMP4) expression was detected in the splanchnopleura and thereafter in the densely packed mesenchymal cells beneath the HIAC. The microarray analyses of early E3 PCLP1+ cells revealed elevated expression of genes known to be involved in the stem cell function. These data suggest that splanchnopleura‐derived PCLP1‐expressing cells give rise to the earliest definitive haematopoietic progenitors.
Long‐term glomerular filtration rate following pediatric liver transplantion
Authors: Wiesmayr Silke , Jungraithmayr Therese C. , Ellemunter Helmut , Stelzmüller Ingrid , Bonatti Hugo , Margreiter Raimund , Zimmerhackl Lothar Bernd 
Published: September 2005

Abstract: In adult patients a significant proportion of chronic renal failure after liver transplantation (LTX) has been described. This was attributed mainly to nephrotoxicity caused by Calcineurin inhibitors (CNI). If these results are transferable to pediatric patients was the aim of this study.Forty‐five pediatric patients with a LTX performed between 1988 and 2003 were evaluated. Glomerular filtration rate was calculated using the Schwartz formula (calculated GFR (cGFR) (mL/min/1.73 m2) = k× height (cm)/serum creatinine (mg/dL)).Median age at LTX was 4 yr (range 0.3–18.1). Pretransplant median cGFR was significantly elevated with 157.5 mL/min/1.73 m2. Within the first 3 months after LTX median cGFR normalized to a median value of 102.7 (p < 0.05 vs. pretransplant cGFR). During long‐term follow‐up median cGFR remained stable with calculated values of 108.0 two years and 112.6 five years after transplantation. Using a linear and an exponential one compartment mathematical modeling of renal function the calculated GFR was stable even for very long observation times (n > 10 yr).Liver insufficiency prior to transplantation was associated with glomerular hyperfiltration. After successful liver transplantation cGFR normalized within the first 3 month and, in contrast to the reported GFR impairment in adult liver transplant recipients, remained stable, even in long‐term follow‐up.
Ocular penetration of oral doxycycline in the horse
Authors: Gilmour Margi A. , Clarke Cyril R. , MacAllister Charles G. , Dedeo Jacqueline M. , Caudell David L. , Morton Rebecca J. , Pugh Martin 
Published: September 2005

AbstractObjective To investigate intraocular penetration of orally administered doxycycline in the normal equine eye and to compare intraocular and serum doxycycline concentrations.Procedures Six mares were administered doxycycline at 10 mg/kg every 12 h by nasogastric tube for 5 days. Blood, aqueous, and vitreous samples were collected on days 1 and 5. All samples were assayed for doxycycline concentrations. Aqueous and vitreous samples were also assayed for protein quantitation.Results Doxycycline was rapidly absorbed after the first dose (Tmaxvalue of 1.42 ± 1.28 h); and elimination of doxycycline occurred slowly (mediant1/2 = 10.88 h). Doxycycline could not be detected in the aqueous on days 1 and 5, nor could it be detected in the vitreous on day 1. On day 5, the mean vitreous doxycycline concentration was 0.17 ± 0.04 µg/mL at 2 h after drug administration.Conclusions Repeated oral administration of doxycycline in the horse resulted in steady state serum concentrations of < 1 µg/mL; however, it did not result in appreciable concentrations of drug in the aqueous and vitreous in normal eyes.
Demonstration of P2Y4 purinergic receptors in the HT‐29 human colon cancer cell line
Authors: Delbro D. S. , Nylund G. , Nordgren S. 
Published: September 2005

Summary 1  The aim of the current study was to investigate the existence of P2Y4 purinergic receptors in the HT‐29 human colon cancer cell line. 2  We utilized Western blots and immunocytochemistry for the analysis. 3  Western blotting demonstrated two bands that could not be found after the antibody had been preabsorbed with the control peptide, suggesting that both bands are related to the P2Y4 purinergic receptor. 4  Immunocytochemistry showed immunoreactivity for the P2Y4 purinergic receptor localized in the cytoplasm of the HT‐29 cells. 5  This is the first demonstration of the protein expression of P2Y4 purinergic receptors in a human colon cancer cell line.
Tourism: A Facilitator of Social Awareness in an Indigenous Mexican Community?
Authors: Greathouse‐Amador Louisa M. 
Published: September 2005

AbstractAs Latin American economies and cultures become increasingly tied to a global political, economic, and social order, indigenous and other marginalized people find themselves at a crossroads where their cultural survival is challenged. Tourism is one important aspect of this new economic order and it is often one of the few resources remaining in countries such as Mexico whose economy has been tied more directly to interests of dominating leaders contributing to this new world order. And while many observers note that tourism often has an exploitative impact on indigenous and marginalized people, this article examines the contradictions in tourism, identifying those economic spaces where the indigenous people have been successful in renegotiating their position with the dominant mestizo group in their community. This article offers provocative insights about the impact of tourism on indigenous people in a community in the northern mountains (Sierra Norte) in Puebla, México. It examines the potential contradictions in tourism under the economic conditions of neoliberalism.
Transcriptional Profiling of Target of RNAIII-Activating Protein, a Master Regulator of Staphylococcal Virulence
Authors: Korem Moshe , Gov Yael , Kiran Madanahally D. , Balaban Naomi 
Published: September 2005

ABSTRACT

Staphylococcus aureus
is a gram-positive bacterium that is part of the normal healthy flora but that can become virulent and cause infections by producing biofilms and toxins. The production of virulence factors is regulated by cell-cell communication (quorum sensing) through the histidine phosphorylation of target of RNAIII-activating protein (TRAP), which is a 21-kDa protein that is highly conserved among staphylococci. Using microarray analysis, we show here that the expression and phosphorylation of TRAP upregulate the expression of most, if not all, toxins known to date, as well as their global regulator
agr
. In addition, we show here that the expression and phosphorylation of TRAP are also necessary for the expression of genes known to be necessary for the survival of the bacteria in a biofilm, like
arc
,
pyr
, and
ure
. TRAP is thus demonstrated to be a master regulator of staphylococcal pathogenesis.
Inhibition of Cell Surface Export of Group A Streptococcal Anchorless Surface Dehydrogenase Affects Bacterial Adherence and Antiphagocytic Properties
Authors: Boël Grégory , Jin Hong , Pancholi Vijay 
Published: September 2005

ABSTRACT

Surface dehydrogenase (SDH) is an anchorless, multifunctional protein displayed on the surfaces of group A
Streptococcus
(GAS) organisms. SDH is encoded by a single gene,
sdh
(
gap
or
plr
) that is essential for bacterial survival. Hence, the resulting nonfeasibility of creating a knockout mutant is a major limiting factor in studying its role in GAS pathogenesis. An insertion mutagenesis strategy was devised in which a nucleotide sequence encoding a hydrophobic tail of 12 amino acids (
337
IVLVGLVMLLLS
348
) was added at the 3′ end of the
sdh
gene, successfully creating a viable mutant strain (M1-SDH
HBtail
). In this mutant strain, the SDH
HBtail
protein was not secreted in the medium but was retained in the cytoplasm and to some extent trapped within the cell wall. Hence, SDH
HBtail
was not displayed on the GAS surface. The mutant strain, M1-SDH
HBtail
, grew at the same rate as the wild-type strain. The SDH
HBtail
protein displayed the same GAPDH activity as the wild-type SDH protein. Although the whole-cell extracts of the wild-type and mutant strains showed similar GAPDH activities, cell wall extracts of the mutant strain showed 5.5-fold less GAPDH activity than the wild-type strain. The mutant strain, M1-SDH
HBtail
, bound significantly less human plasminogen, adhered poorly to human pharyngeal cells, and lost its innate antiphagocytic activity. These results indicate that the prevention of the cell surface export of SDH affects the virulence properties of GAS. The anchorless SDH protein, thus, is an important virulence factor.
Enteropathogenic
Escherichia coli
Type III Effectors EspG and EspG2 Alter Epithelial Paracellular Permeability
Authors: Matsuzawa Takeshi , Kuwae Asaomi , Abe Akio 
Published: September 2005

ABSTRACT

Enteropathogenic
Escherichia coli
(EPEC) delivers a subset of effectors into host cells via a type III secretion system. Here we show that the type III effector EspG and its homologue EspG2 alter epithelial paracellular permeability. When MDCK cells were infected with wild-type (WT) EPEC, RhoA was activated, and this event was dependent on the delivery of either EspG or EspG2 into host cells. In contrast, a loss of transepithelial electrical resistance and ZO-1 disruption were induced by infection with an
espG/espG2
double-knockout mutant, as was the case with the WT EPEC, indicating that EspG/EspG2 is not involved in the disruption of tight junctions during EPEC infection. Although EspG- and EspG2-expressing MDCK cells exhibited normal overall morphology and maintained fully assembled tight junctions, the paracellular permeability to 4-kDa dextran, but not the paracellular permeability to 500-kDa dextran, was greatly increased. This report reveals for the first time that a pathogen can regulate the size-selective paracellular permeability of epithelial cells in order to elicit a disease process.
Th1 Cytokines Are Essential for Placental Immunity toListeria monocytogenes
Authors: Barber Ellen M. , Fazzari Melissa , Pollard Jeffrey W. 
Published: September 2005

ABSTRACTThe fetal allograft poses an immunological challenge: how is it protected while immunity to pathogens, particularly those that replicate in the placenta, is maintained? Several theories have been proposed to explain this fetal protection, including a pregnancy-based bias towards a Th2 rather than Th1 cytokine profile in order to avoid generating cytotoxic T cells that could threaten the fetus.Listeria monocytogenespreferentially replicates in the placenta and systemically requires a Th1 response for sterile eradication. In the placenta, the Th1 cytokines tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) are also synthesized in response to this pathogen, without fetal loss. Here we show, by using mice homozygous for null mutations in either the cytokine or cytokine receptor genes, a requirement for both TNF-α and IFN-γ signaling for an effective placental immune response toL. monocytogenes. However, T cells were not recruited to the placenta. Genetic studies in which the fetal component of the placenta was genetically different from the mother indicated that both the production of and response to these cytokines were maternal. Despite the requirement for these cytokines, the early recruitment of neutrophils to the placenta was normal. Consequently, the bacterium appeared to be delayed in its colonization of this organ and did not fully gain hold until 72 h postinfection. These data show a requirement for Th1 cytokines during pregnancy for effective immunity and indicate that a bias away from Th1 cytokine synthesis is not a necessary prerequisite of pregnancy.
Massive Destruction of Malaria-Parasitized Red Blood Cells despite Spleen Closure
Authors: Krücken Jürgen , Mehnert Liv I. , Dkhil Mohamed A. , El-Khadragy Manal , Benten W. Peter M. , Mossmann Horst , Wunderlich Frank 
Published: September 2005

ABSTRACT

It is currently accepted that malaria-parasitized red blood cells (pRBC) are eliminated, like senescent erythrocytes, phagocytically by macrophages in the red pulp of the spleen. Here, however, we show that self-healing
Plasmodium chabaudi
malaria activates spleen closure in C57BL/6 mice. Confocal laser scanning microscopy revealed that spleen closing was manifested by elimination of entry into the red pulp of 3-μm polystyrol particles, pRBC, and nonparasitized red blood cells but not of bovine serum albumin. This spleen closure did not reflect a reduction in the number of phagocytic cells, as shown by flow cytometry, whereas marginal zone macrophages (MZM) were lost and red pulp macrophages entered the white pulp. Splenic trapping of pBRC was strongly reduced in the absence of MZM and marginal metallophilic macrophages (MMM), as it is in noninfected mice with a disrupted lymphotoxin β receptor (LTβR
−/−
), and it was still significantly reduced when the number of MZM and MMM was diminished, as in tumor necrosis factor alpha-deficient (TNF-α
−/−
) mice. Moreover, mice deficient in TNF-α, tumor necrosis factor receptor I (TNFRI
−/−
), and LTβR exhibited progressive impairment in malaria-induced spleen closing. Treatment of C57BL/6 mice with TNF-α induced loss of MZM and spleen closing by about 20%. Our data indicate that TNF/TNFRI signaling is involved in regulating malaria-induced spleen closure, which is maximal during crisis, when parasitemia declines more than 100-fold. Consequently, the vast majority of pRBC cannot be destroyed by the spleen during crisis, suggesting that the known sophisticated sequestration system of
Plasmodium
parasites did not evolve to avoid splenic clearance.
The Surface-Associated Protein of
Staphylococcus saprophyticus
Is a Lipase
Authors: Sakinc Türkan , Woznowski Magdalena , Ebsen Michael , Gatermann Sören G. 
Published: September 2005

ABSTRACT

Staphylococcus saprophyticus
surface-associated protein (Ssp) was the first surface protein described for this organism. Ssp-positive strains display a fuzzy layer of surface-associated material in electron micrographs, whereas Ssp-negative strains appear to be smooth. The physiologic function of Ssp, however, has remained elusive. To clone the associated gene, we determined the N-terminal sequence, as well as an internal amino acid sequence, of the purified protein. We derived two degenerate primers from these peptide sequences, which we used to identify the
ssp
gene from genomic DNA of
S. saprophyticus
7108. The gene was cloned by PCR techniques and was found to be homologous to genes encoding staphylococcal lipases. In keeping with this finding, strains 7108 and 9325, which are Ssp positive, showed lipase activity on tributyrylglycerol agar plates, whereas the Ssp-negative strain CCM883 did not. Association of enzyme activity with the cloned DNA was proven by introducing the gene into
Staphylococcus carnosus
TM300. When wild-type strain 7108 and an isogenic mutant were analyzed by transmission electron microscopy, strain 7108 exhibited the fuzzy surface layer, whereas the mutant appeared to be smooth. Lipase activity and the surface appendages could be restored by reintroduction of the cloned gene into the mutant. Experiments using immobilized collagen type I did not provide evidence for the involvement of Ssp in adherence to this matrix protein. Our experiments thus provided evidence that Ssp is a surface-associated lipase of
S. saprophyticus
.
THP-1 Monocytes Up-Regulate Intercellular Adhesion Molecule 1 in Response to Pneumolysin fromStreptococcus pneumoniae
Authors: Thornton Justin , McDaniel Larry S. 
Published: September 2005

ABSTRACTPneumolysin (PLY) is a major virulence factor ofStreptococcus pneumoniaethat elicits a variety of proinflammatory responses from cells of the host immune system. Intercellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule involved in leukocyte trafficking toward inflammatory stimuli in extravascular sites. In this study, we evaluated the effect of PLY on expression of ICAM-1 in THP-1 monocytic cells exposed toS. pneumoniae. Exposure of cells to PLY-expressingS. pneumoniaestrain WU2 for 6 h led to significantly higher levels of ICAM-1 message than those in cells exposed to either medium alone or ΔPLY1, a PLY-negative isogenic mutant of WU2. Cells exposed to purified recombinant PLY also showed a dose-dependent increase in ICAM-1 mRNA compared to cells exposed to medium alone. Exposure to recombinant PLY containing a single amino acid substitution (Trp433→Phe) that decreases cytolytic activity did not increase ICAM-1 mRNA to levels seen with wild-type PLY. In addition, THP-1 cells exposed to wild-type strain WU2 or D39 had increased ICAM-1 on their surface compared to cells exposed to medium alone or their PLY-negative isogenic mutants ΔPLY1 and ΔPLY2, respectively. These data indicate that PLY induces transcription and production of a cell adhesion molecule involved in the inflammatory response that may play a role in pneumococcal infection.
Activation and Mitogen-Activated Protein Kinase Regulation of Transcription Factors Ets and NF-κB in Mycobacterium-Infected Macrophages and Role of These Factors in Tumor Necrosis Factor Alpha and Nitric Oxide Synthase 2 Promoter Function
Authors: Lee Seong-Beom , Schorey Jeffrey S. 
Published: September 2005

ABSTRACTPrevious studies have shown that primary murine macrophages infected withMycobacterium aviumproduced lower levels of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase 2 (NOS2) compared to cells infected with nonpathogenicMycobacterium smegmatis. TNF-α and NOS2 levels correlated with and were dependent on the activation of mitogen-activated protein kinases (MAPKs) p38 and extracellular signal-regulated kinase 1/2 (ERK1/2). To define the macrophage transcriptional responses dependent on ERK1/2 activation following a mycobacterial infection, we used RAW 264.7 cells transfected with a TNF-α or NOS2 promoter vector. We determined that macrophages infected withM. aviumcompared toM. smegmatisshowed diminished TNF-α and NOS2 promoter activity. A more pronounced difference in promoter activity was observed when only the consensus ETS and NF-κB binding sites were used as promoters. Mutational analysis of the ETS and NF-κB binding sites present on the TNF-α and NOS2 promoters, respectively, showed that these sites were essential for a functional promoter. Moreover, the Ets/Elk but not the NF-κB transcriptional response was dependent on ERK1/2. This correlated with the requirement for ERK1/2 in TNF-α but not NOS2 promoter activity. Our data indicate that the increased Ets/Elk and NF-κB promoter activities associated withM. smegmatis-infected macrophages are responsible, at least in part, for the increased TNF-α and NOS2 production observed in these infected cells and that ERK1/2 is required for Ets/Elk activity and full TNF-α production.
Evaluation of Three
Pichia pastoris
-Expressed
Plasmodium falciparum
Merozoite Proteins as a Combination Vaccine against Infection with Blood-Stage Parasites
Authors: Zhang Dongmei , Pan Weiqing 
Published: September 2005

ABSTRACT

Because invasion of erythrocytes by
Plasmodium falciparum
merozoites involves multiple receptor-ligand interactions, it may be necessary to develop a multivalent malaria vaccine that is comprised of distinct parasite ligands. PfAMA-1, PfMSP1, and PfEBA-175 are merozoite proteins that play important roles in invasion. We have constructed a PfCP-2.9 chimeric protein consisting of PfAMA-1 and PfMSP1 and tested it for immunogenicity in animal models and humans. The F2 subdomain of PfEBA-175 (PfEBA-175II F2) was identified as the binding domain for glycophorin A on erythrocytes. In this study, we used the codon frequencies of the yeast
Pichia pastoris
to redesign and synthesize a gene encoding the F2 domain. We found that the codon-optimized gene was expressed at a high level in
P. pastoris
as a soluble protein with a yield of about 300 mg/liter. The expressed protein was able to bind normal erythrocytes but not those treated with neuraminidase or trypsin. Moreover, the protein was recognized by the sera of malaria patients and was highly immunogenic in mice, rabbits, and rhesus monkeys. Immunoglobulin G isolated from both immunized rabbits and monkeys inhibited in vitro parasite growth. Immunization of animals with a combination of PfEBA-175II F2 and PfCP-2.9 did not result in antigen (Ag) competition in animals. Moreover, antibodies to both PfEBA-175II F2 and PfCP-2.9, isolated from rabbits immunized with both constructs, inhibited parasite growth in vitro. The combination of high yield, functional folding, antibody inhibition, and lack of Ag competition provides support for inclusion of these merozoite proteins in a combination vaccine against infection with blood-stage parasites.