bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution and species characteristics of the Culicoides biting midge fauna of South Africa
Authors: Rawlings P. , Meiswinkel R. , Labuschange K. , Welton N. , Baylis M. , Mellor P. S. 
Published: September 2003

Abstract.  1. Monthly light trap collections over 2 years at 39 sites across South Africa captured over 3 000 000 Culicoides of 86 species, some of them known vectors of African horse sickness and bluetongue viruses.2. To aid disease control and risk evaluation, cluster analysis and association measurements were carried out on species present at each site. Six species occurred at almost all sites. From the remaining 80 species, eight clusters were identified at > 48% similarity.3. Culicoides citroneus and C. krameri were characteristic of cluster 8, C. loxodontis of cluster 4, and two numbered, but un‐named, species, C. #119 and C. #89, of cluster 5.4. Multiple anova and multiple discriminant analysis on the climatic and geographic parameters of sites in each cluster gave two significant discriminant functions that explained 91.5% of the variance between clusters. Function 1 contrasted sites with high cold cloud duration and high vegetation index with sites with high wind speeds. Function 2 contrasted upland clusters that also had high cold cloud duration with hotter, lower altitude sites.5. Species associations were explained in terms of biotic provinces, based on ecogeographic factors that have previously been useful to describe communities of birds.6. None of the clusters was ideal for siting an African horse sickness‐vector free quarantine station as C. imicola and C. bolitinos, the main vectors, were found in all clusters but in very low abundance in cluster 5. The analysis provides a firm basis for studying the changing patterns of species distribution under varying climatic influences.
Influence of host plant heterogeneity on the distribution of a birch aphid
Authors: Johnson Scott N. , Elston David A. , Hartley Susan E. 
Published: September 2003

Abstract.  1. The spatial and temporal abundance of the aphid Euceraphis betulae was investigated in relation to heterogeneity in host plant (Betula pendula) vigour and pathogenic stress. The performance of aphids feeding on vigorous and stressed foliage was also examined.2. The plant stress and plant vigour hypotheses have been suggested as opposing ways in which foliage quality influences herbivore abundance. In many plants, however, vigorous growing foliage co‐exists with stressed or damaged foliage.3. There was a negative correlation between branch growth (vigour) and branch stress (leaf chlorosis), with the most vigorous branches displaying little or no stress, and the most stressed branches achieving poor growth. There was a similar negative correlation between vigour and stress at the level of individual trees, which themselves represented a continuum in quality.4. At the beginning of the season, E. betulae were intermittently more abundant on vigorous branches than on branches destined to become stressed, but aphids became significantly more abundant on stressed branches later in the season, when symptoms of stress became apparent. Similar patterns of aphid abundance were seen on vigorous and stressed trees in the following year.5. Euceraphis betulae performance was generally enhanced when feeding on naturally stressed B. pendula leaves, but there was some evidence for elevated potential reproduction when feeding on vigorous leaves too.6. Overall, plant stress probably influences E. betulae distribution more than plant vigour, but the temporal and spatial variability in plant quality suggests that plant vigour could play a role in aphid distribution early in the season.
Are honey bees' foraging preferences affected by pollen amino acid composition?
Authors: Cook Samantha M. , Awmack Caroline S. , Murray Darren A. , Williams Ingrid H. 
Published: September 2003

Abstract.  1. Although pollen is a vital nutritional resource for honey bees, Apis mellifera, the influence of pollen quality on their foraging behaviour is little understood.2. In choice‐test experiments, bees showed no innate pollen‐foraging preferences, but preferred oilseed rape Brassica napus pollen over field bean Vicia faba pollen after previous foraging experience of oilseed rape.3. The free amino acid content of oilseed rape and field bean pollen was compared using high‐performance liquid chromatography. Oilseed rape pollen contained a greater proportion of the most essential amino acids required by honey bees (valine, leucine, and isoleucine) than field bean, suggesting that oilseed rape pollen is of greater nutritional quality for honey bees than is field bean pollen.4. Honey bee foraging preferences appeared to reflect pollen quality. The hypothesis that pollen amino acid composition affects the foraging behaviour of honey bees is discussed.
Habitat edges as a potential ecological trap for an insect predator
Authors: Ries Leslie , Fagan William F. 
Published: September 2003

Abstract.  1. Ecological traps, where animals actively select poor habitat for reproduction over superior habitat, are generally associated with birds at forest edges. This study examines oviposition preference, predation, and parasitism rates in the mantid Stagmomantis limbata to determine the potential generality of this phenomenon.2. Egg case (oothecae) densities were measured across two edge types (cottonwood and desert scrub) within desert riparian ecosystems. A positive edge effect in oothecae density was found with an approximate three‐fold increase in density at cottonwood (Xedge = 0.05 oothecae/100 m2 vs. Xinterior = 0.015 oothecae/100 m2) and desert scrub (Xedge = 0.20 oothecae/100 m2 vs. Xinterior = 0.06 oothecae/100 m2) edges (P < 0.01).3. Rates of bird predation were significantly higher for oothecae at desert scrub edges and showed a trend of higher predation rates at cottonwood edges, suggesting that riparian habitat edges may be acting as an ecological trap for this mantid species. There was no effect of edges on oothecal parasitism rates.4. These results provide an example of the effect of habitat edges on a generalist insect predator and indicate that an ecological trap may exist with respect to one of its natural enemies.
Gall size determines the structure of theRabdophaga strobiloideshost–parasitoid community
Authors: Van Hezewijk Brian H. , Roland Jens 
Published: September 2003

Abstract. 1. The relationship between gall size and mortality of the willow pinecone gall midgeRabdophaga strobiloides(Diptera: Cecidomyiidae) was examined by determining the fate of all galls in a 30‐ha area in central Alberta, Canada over 4 years. It was found that gall size has a large effect on the type and intensity of mortality experienced by the gall midge, and consequently this factor has the potential to influence the dynamics of the host–parasitoid interaction through the creation of phenotypic refuges.2. Total midge mortality ranged from 51% to 78% over the course of the study and was dominated by parasitism byTorymus cecidomyiae(Hymenoptera: Torymidae) andGastrancistrussp. (Hymenoptera: Pteromalidae) as well as predation by birds. Gall size had a strong, non‐linear effect on the attack rates of each of these natural enemies.3. Birds attacked the smallest size classes.Torymus cecidomyiaepreferentially attacked medium diameter galls and thus avoided predation by birds in smaller galls.Gastrancistrussp. preferentially attacked the largest galls and consequently suffered lower rates of predation by bothT. cecidomyiaeand birds.4. This study emphasises the importance of understanding the interactions among mortality factors in order to describe adequately the susceptibility ofR. strobiloidesto parasitism and predation, and ultimately its population dynamics.
Apoptosis induction by interleukin‐2‐activated cytotoxic lymphocytes in a squamous cell carcinoma cell line and Daudi cells – involvement of reactive oxygen species‐dependent cytochrome c and reactive oxygen species‐independent apoptosis‐inducing factors
Authors: Yamamoto Tetsuya , Ueta Eisaku , Osaki Tokio 
Published: September 2003

SummaryInvestigation of the induction of apoptosis by cytotoxic lymphocytes has mainly focused on the signalling associated with Fas and its adaptor proteins. The signal pathway via mitochondria, however, has not been sufficiently elucidated in cytotoxic lymphocyte‐induced apoptosis. We examined the release of mitochondrial proapoptotic factors by lymphokine‐activated killer (LAK) cells in two cell lines. LAK cell‐induced DNA fragmentation of the target cells was suppressed to approximately 50% of control levels by the addition of neutralizing monoclonal antibody to Fas and a granzyme B inhibitor. When intracellular reactive oxygen species (ROS) were scavenged, the LAK cell‐induced DNA fragmentation was decreased to approximately 60% of the non‐treated cell level. Co‐cultivation of Daudi cells with LAK cells increased cytosolic and mitochondrial ROS levels. Activation of procaspase‐3 and apoptosis by treatment of oral squamous cell carcinoma cells (OSC) with LAK cells was partially inhibited by pretreatment of OSC cells with ROS scavengers and mitochondrial complex inhibitors. Furthermore, cytochrome c and apoptosis‐inducing factor (AIF) were released from mitochondria by OSC cell treatment with supernatants of LAK cells. The supernatant‐induced cytochrome c release was suppressed by mitochondrial complex inhibitors, but the inhibitors did not inhibit the release of AIF. These results indicate that LAK cells induce target cell apoptosis via not only the Fas/Fas ligand system and granzyme B, but also ROS‐dependent cytochrome c and ROS‐independent AIF release.
A Salmonella typhi OmpC fusion protein expressing the CD154 Trp140–Ser149 amino acid strand binds CD40 and activates a lymphoma B‐cell line
Authors: Vega Mario I. , Santos‐Argumedo Leopoldo , Huerta‐Yepez Sara , Luría‐Perez Rosendo , Ortiz‐Navarrete Vianney , Isibasi Armado , González‐Bonilla Cesar R. 
Published: September 2003

SummaryCD154 is a type II glycoprotein member of the tumour necrosis factor (TNF) ligand family, which is expressed mainly on the surface of activated T lymphocytes. The interaction with its receptor CD40, plays a central role in the control of several functions of the immune system. Structural models based on the homology of CD154 with TNF and lymphotoxin indicate that binding to CD40 involves three regions surrounding amino acids K143, R203 and Q220, and that strands W140–S149 and S198–A210 are critical for such interactions. Also, it has been reported that two recombinant CD154 fragments, including amino acid residues Y45–L261 or E108–L261 are biologically active, whereas other polypeptides, including S149–L261, are not. Therefore, we decided to construct a fusion protein inserting the W140‐S149 amino acid strand (WAEKGYYTMS) in an external loop of the outer membrane protein C (OmpC) from Salmonella enterica serovar Typhi and assess its ability to bind CD40 and activate B cells. The sodium dodecyl sulphate–polyacrylamide gel electrophoresis demonstrated that the chimeric OmpC–gp39 protein conserved its ability to form trimers. Binding to CD40 was established by three variants of enzyme‐linked immunosorbent assay, a direct binding assay by coating plates with a recombinant CD40–Fc protein and through two competition assays between OmpC–gp39 and recombinant CD154 or soluble CD40–Fc. Flow cytometry analysis demonstrated that OmpC–gp39 increased the expression levels of major histocompatibility complex II, CD23, and CD80, in Raji human B‐cell lymphoma similarly to an antibody against CD40. These results further support that the CD154/CD40 interaction is similar to the TNF/TNF receptor. This is the first report of a bacterial fusion protein containing a small amino acid strand form a ligand that is able to activate its cognate receptor.
Selective regulation of CD40 expression in murine dendritic cells by thiol antioxidants
Authors: Iijima Norifumi , Yanagawa Yoshiki , Iwabuchi Kazuya , Onoé Kazunori 
Published: September 2003

SummaryInteraction of CD40 on dendritic cells (DC) with CD40 ligand induces interleukin‐12 (IL‐12) production by these DC during the antigen presentation. Thus, the level of CD40 expression appears to influence the capability of DC to induce a T helper 1 (Th1) response. However, it is not fully understood how CD40 expression on DC is regulated. In the present study, we examined the effects of the reducing agents, N‐acetyl‐l‐cysteine (NAC) and reduced glutathione (GSH), on tumour necrosis factor‐α (TNF‐α)‐induced phenotypic changes in murine DC. TNF‐α markedly increased the expression on DC of major histocompatibility complex (MHC) and the costimulatory molecules, CD40, CD80 and CD86. Both NAC and GSH completely abolished the TNF‐α‐induced enhancement of CD40 expression, but had no considerable effect on the expression of CD80, CD86 and MHC. The marked decrease of CD40 protein with NAC was also detected by Western blotting, but was not associated with the expression level of CD40 mRNA in DC. Thus, NAC appears to reduce CD40 expression on DC by regulating a post‐transcriptional pathway. The inhibitory effect of NAC or GSH on TNF‐α‐induced CD40 expression was released by simply removing these agents from the culture. In contrast, culture of TNF‐α‐treated DC with NAC or GSH markedly decreased the expression of CD40 within 12 hr. These results demonstrate that reducing agents selectively, rapidly and reversibly regulate CD40 expression on DC, which may eventually affect the capability of DC for Th1/Th2 polarization.
Fas ligand‐induced murine pulmonary inflammation is reduced by a stable decoy receptor 3 analogue
Authors: Wortinger Mark A. , Foley Joseph W. , Larocque Patrick , Witcher Derrick R. , Lahn Michael , Jakubowski Joseph A. , Glasebrook Andrew , Song Ho Yeong 
Published: September 2003

SummaryFas ligand (FasL)‐induced lung inflammation has recently been suggested to play an important role in the pathogenesis of acute respiratory disease syndrome (ARDS). In order to further explore this connection, we established a FasL‐induced murine model of pulmonary inflammation. Instillation of recombinant FasL (rFasL) into the lung induced neutrophil infiltration and increased pulmonary permeability, as evidenced by increased total protein in the airspace; both occur in patients with ARDS. These effects were accompanied with a rapid induction of proinflammatory mediators: cytokine granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and the chemokines macrophage inflammatory protein‐2 (MIP‐2) and KC. Pretreatment with a FasL antagonist, a decoy receptor 3 analogue (DcR3 analogue), reduced neutrophil infiltration into the airspace and resulted in a highly significant reduction in the levels of GM‐CSF, MIP‐2 and KC in bronchoalveolar lavage (BAL) fluid. We postulate that rFasL may be responsible for induction of proinflammatory chemokines and cytokines in the lung, which in turn attract neutrophil infiltration into the airspace. This proinflammatory process and the associated pulmonary permeability may, in part, explain the association of FasL with severe pulmonary inflammation, such as ARDS, and shed new light on FasL and its role in lung injury.
Characterization of CC‐chemokine receptor 7 expression on murine T cells in lymphoid tissues
Authors: Bjorkdahl Olle , Barber Karen A. , Brett Sara J. , Daly Maria G. , Plumpton Christopher , Elshourbagy Nabil A. , Tite John P. , Thomsen Lindy L. 
Published: September 2003

SummaryExpression of the lymph node homing and CC‐chemokine receptor 7 (CCR7), with L‐selectin (CD62L), has been shown to divide human memory T cells into two functionally distinct subsets. We generated a polyclonal antibody against murine CCR7 and used this antibody to study CCR7 expression on murine T‐cell subsets. Using flow cytometric staining of T cells for visualisation expression of CCR7 in association with CD62L and CD44, a major population of CD4 or CD8 T cells expressing CCR7 were found to be CD62Lhigh CD44low, which would suggest a naïve cell phenotype. By analogy with human studies, memory cells could be subdivided into CCR7high CD62Lhigh CD44high (central memory) and CCR7low CD62Llow CD44high (effector memory). The proportions of these populations were different in lymph node, blood and spleen. Functional, short‐term in vitro polyclonal stimulation of blood, spleen and lymph node cells from naive mice demonstrated that CCR7high CD4 T cells produced predominantly interleukin (IL)‐2, whereas CCR7low CD4 T cells produced both IL‐2 and interferon‐γ (IFN‐γ). However, in contrast to previously published reports, the CCR7high CD8 T‐cell subpopulation produced both IFN‐γ and IL‐2. Analysis of effector T cells, induced by immunization in vivo, showed that a proportion of activated naïve CD4 T cells down‐regulated CCR7 only after multiple cell divisions, and this coincided with the down‐regulation of CD62L and production of IL‐4 and IFN‐γ. Finally, analysis of effector T cells during the phase of maximal clonal expansion of secondary immune responses in vivo indicated that the vast majority of both IL‐2‐ and IFN‐γ‐producing cells are CCR7low, while few cytokine‐expressing CCR7high T cells were detected. Our results support the hypothesis, developed from studies with human cells, that CCR7 may separate functionally different murine memory T‐cell subpopulations, but indicate additional complexity in that CCR7high CD8 T cells also may produce IFN‐γ.
Phage display of human antibodies from a patient suffering from coeliac disease and selection of isotype‐specific scFv against gliadin
Authors: Rhyner Claudio , Weichel Michael , Hübner Philipp , Achatz Gernot , Blaser Kurt , Crameri Reto 
Published: September 2003

SummaryCoeliac disease (CD), a gastrointestinal illness characterized by intestinal malabsorption, results from gluten intolerance accompanied with immunological responses towards gliadin, an ethanol‐soluble protein fraction of wheat and other cereals. The role of gliadin in eliciting immune responses in CD is still partly unclear; however, the occurrence of anti‐gliadin in the sera of patients suffering from CD correlates well with clinical symptoms. In this work we report the construction of isotype‐specific, phage‐displayed scFv libraries from peripheral blood lymphocytes of a patient with CD and from a healthy control individual. VH and VL chains were amplified by reverse transcription–polymerase chain reaction (RT–PCR) using a set of oligonucleotides recognizing all human variable gene families. The three scFv libraries (IgA, IgG and IgM) were selectively enriched for gliadin‐binding phage. After four rounds of affinity selection, polyclonal enrichment of gliadin‐binding phage was observed in all libraries from the CD patient but in none from the healthy donor. Phagemid particles generated from single clones were demonstrated to be gliadin‐specific, as shown by strongly positive enzyme‐linked immunosorbent assay (ELISA) and BiaCore signals. The VH and VL chains from samples of these monoclonal isotype‐specific phage were sequenced to identify the most common variable regions used by the immune system to elicit antibody responses against gliadin.
Simultaneous administration of a low‐dose mixture of donor bone marrow cells and splenocytes plus adenovirus containing the CTLA4Ig gene result in stable mixed chimerism and long‐term survival of cardiac allograft in rats
Authors: Jin Yongzhu , Zhang Qingyin , Hao JIE , Gao Xiang , Guo Yinglu , Xie Shusheng 
Published: September 2003

SummaryT‐cell costimulatory blockade combined with donor bone marrow transfusion may induce mixed chimerism, rendering robust tolerance in transplanted organs and cells. However, most protocols entail high doses of donor bone marrow cells (BMCs) or repeated administration of costly agents that block costimulatory pathways, thus delaying clinical development. To circumvent these shortcomings, we developed a strategy in which the dosage of donor BMCs was reduced but compensated by donor splenocytes (SPLCs). Furthermore, repeated administration of costly agents was replaced with a single injection of adenovirus expressing a gene of interest. In rat cardiac transplantation models, cardiac allografts from DA (RT‐1a) rats were transplanted heterotopically into the abdomen of LEW (RT‐11) recipient rats. Immediately after cardiac transplantation, an adenovirus vector (AdCTLA4Ig; 5 × 109plaque‐forming units) containing the gene for CTLA4Ig was administered to recipients (n = 6) simultaneously with a low dose of donor BMCs (1 × 108/rat) and SPLCs (5 × 107/rat) via the portal vein. The treated LEW recipient rats developed long‐lasting mixed chimerism (>10% at >100 days) and exhibited long‐term cardiac allografts (mean survival time of > 200 days) compared with control recipients. Moreover, recipients displaying long‐lasting mixed chimerism accepted subsequent donor skin allografts while promptly rejecting third‐party skin allografts. These results suggest that blockade of the CD28‐B7 pathway, using adenovirus‐mediated CTLA4Ig gene transfer, in concert with a low dosage of donor BMCs and SPLCs, may represent a feasible strategy to induce stable mixed chimerism and permit long‐term survival of cardiac allografts.
Paradoxical effects of interleukin‐10 on the maturation of murine myeloid dendritic cells
Authors: Commeren Dianne L. , Van Soest Peter L. , Karimi Khalil , Löwenberg Bob , Cornelissen Jan J. , Braakman Eric 
Published: September 2003

SummaryThe immunoregulatory cytokine, interleukin‐10 (IL‐10), has been shown to inhibit the maturation of human myeloid dendritic cells (DC). In the present study, we demonstrate that IL‐10 has paradoxical effects on the maturation of murine myeloid bone marrow‐derived DC. On the one hand, IL‐10 inhibits the maturation of murine myeloid DC. The addition of IL‐10 to granulocyte–macrophage colony‐stimulating factor (GM‐CSF)‐supported murine BM‐derived DC cultures reduced the frequency of major histocompatibility complex (MHC) class IIbright cells. These IL‐10‐pretreated DC have a reduced capacity to stimulate T cells in an allogeneic mixed leucocyte reaction. On the other hand, however, and in contrast to the effects of IL‐10 on human DC, we found that the addition of IL‐10 from the initiation of the culture onwards induced an up‐regulation of the expression of the costimulatory molecules CD40, CD80 and CD86 on murine myeloid DC, as compared to DC generated with GM‐CSF only. Moreover, a subpopulation of IL‐10‐pretreated MHC class IIdim DC lacked the capacity to take up dextran‐fluorescein isothiocyanate (FITC), a feature of DC maturation. Taken together, our data demonstrate that the generation of murine myeloid DC in the presence of IL‐10 results in a population of incompletely matured MHC class IIdim CD80+ CD86+ DC. These DC lack T‐cell stimulatory capacity, suggesting a role for IL‐10 in conferring tolerogenic properties on murine myeloid DC.