bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability of resistance to Phytophthora infestans in potato: an international evaluation
Authors: Forbes G. A. , Chacón M. G. , Kirk H. G. , Huarte M. A. , Van Damme M. , Distel S. , Mackay G. R. , Stewart H. E. , Lowe R. , Duncan J. M. , Mayton H. S. , Fry W. E. , Andrivon D. , Ellissèche D. , Pellé R. , Platt H. W. , MacKenzie G. , Tarn T. R. , Colon L. T. , Budding D. J. , Lozoya‐Saldaña H. , Hernandez‐Vilchis A. , Capezio S. 
Published: June 2005

Ten institutions in nine countries joined together to test the stability of resistance of 14 potato genotypes to the oomycete pathogen Phytophthora infestans in three separate trials. Seven of the genotypes were tested in one trial involving seven locations, and all 14 were tested in two subsequent trials, each involving eight locations. Stability of resistance was tested with nonparametric tests and with an additive main effects and multiplicative interaction (AMMI) model. Overall, resistance to P. infestans was robust; resistant genotypes were consistently resistant in all locations and trials. The nonparametric analysis indicated that specific genotypes were basically stable across sites for resistance. In trial 3, the Z statistic for overall stability was significant at 0·05%, indicating a significant level of interaction across the trial, but there were no significant interactions for specific genotypes in this trial. The genotype by environment (G × E) effect of the AMMI model was highly significant in both trials, but the mean square of G × E was less than 10% of the genotype effect in each trial. The first two principal components (PCA1 and PCA2) of the AMMI analyses together explained 75 and 80% of the interaction effects in trials 2 and 3, respectively. Based on both nonparametric and AMMI analyses, Ecuador and Argentina were locations of relatively high interaction effects for both trials 2 and 3, although in Ecuador this interaction was not associated with any particular potato genotype. Other locations also had high interaction effects, but these occurred in only one trial. The genotypes Chata Blanca and, to a lesser extent, Torridon were relatively unstable in trials 2 and 3, but in the case of Torridon, resistant, this did not represent a significant loss of resistance.
Responses to Free Lipopolysaccharide and Escherichia coli by Normal Human Intestinal Macrophages, Following their Migration out of the Lamina Propria
Authors: Austin A. S. , Judge H. M. , Robins R. A. , Cockayne A. , Mahida Y. R. 
Published: June 2005

AbstractIntestinal macrophage responses to luminal bacteria and their constituents are important in mucosal inflammatory responses. We investigated the responses of intestinal macrophages to free lipopolysaccharide (LPS) and Escherichia coli. Macrophages were isolated from normal terminal ileum and colon by allowing them to migrate out of the lamina propria of mucosal samples denuded of epithelial cells. Following exposure to free LPS or fluorescein‐labelled E. coli, responsiveness was studied by intracellular expression of tumour necrosis factor‐α (TNF‐α). CD14, CD33, CD68, TLR2 and TLR4 expression was studied by fluorescence‐activated cell sorter (FACS). TLR and NOD2 expression was confirmed by reverse‐transcriptase polymerase chain reaction (RT‐PCR). CD14 was expressed by 36.5 ± 4.0% of the macrophages obtained following migration out of the lamina propria. These cells also expressed TLR2, TLR4 and NOD2. Of cells exposed to free LPS or those that had taken up E. coli, a greater proportion of CD14+ than CD14– macrophages expressed intracellular TNF‐α. Moreover, a greater proportion of macrophages (CD14+ and CD14–) demonstrated responses to E. coli than free LPS. In conclusion, a proportion of macrophages obtained following migration out of the lamina propria of normal terminal ileal and colonic mucosal samples express CD14, TLR2 and TLR4. These cells respond to free LPS and E. coli, as demonstrated by the expression of TNF‐α.
Milk‐Derived GM3 and GD3 Differentially Inhibit Dendritic Cell Maturation and Effector Functionalities
Authors: Brønnum H. , Seested T. , Hellgren L. I. , Brix S. , Frøkiær H. 
Published: June 2005

AbstractGangliosides are complex glycosphingolipids, which exert immune‐modulating effects on various cell types. Ganglioside GD3 and GM3 are the predominant gangliosides of human breast milk but during the early phase of lactation, the content of GD3 decreases while GM3 increases. The biological value of gangliosides in breast milk has yet to be elucidated but when milk is ingested, dietary gangliosides might conceptually affect immune cells, such as dendritic cells (DCs). In this study, we address the in vitro effect of GD3 and GM3 on DC effector functionalities. Treatment of bone marrow‐derived DCs with GD3 before lipopolysaccharide‐induced maturation decreased the production of interleukin‐6 (IL‐6), IL‐10, IL‐12 and tumor necrosis factor‐α as well as reduced the alloreactivity in mixed leucocyte reaction (MLR). In contrast, only IL‐10 and IL‐12 productions were significantly inhibited by GM3, and the potency of DCs to activate CD4+ cells in MLR was unaffected by GM3. However, both gangliosides suppressed expression of CD40, CD80, CD86 and major histocompatibility complex class II on DCs. Because GD3 overall inhibits DC functionalities more than GM3, the immune modulating effect of the ganglioside fraction of breast milk might be more prominent in the commencement of lactation during which the milk contains the most GD3.
A Full Flora, but not Monocolonization by Escherichia coli or Lactobacilli, Supports Tolerogenic Processing of a Fed Antigen
Authors: Rask C. , Evertsson S. , Telemo E. , Wold A. E. 
Published: June 2005

AbstractFed protein undergoes processing and coupling to major histocompatibility complex (MHC) II molecules during passage through the intestinal epithelium, generating a tolerogenic form of the antigen in serum. Transfer of this factor to naïve animals induces tolerance in the recipient. In this study, we investigate what impact colonization with Gram‐positive (Lactobacillus plantarum) or Gram‐negative (Escherichia coli) bacteria has on tolerogenic processing in the gut. Germ‐free (GF), monocolonized or conventional mice were fed ovalbumin (OVA), and their serum was collected and transferred to naïve conventional recipients that were tested for delayed‐type hypersensitivity against OVA after parenteral immunization. A transferable tolerogenic factor was produced by conventional mice, but not by mice that were germ free or monocolonized with either E. coli or L. plantarum. Conventional, but neither GF nor monocolonized mice showed upregulation of MHCII expression in the epithelium of small intestine. The results suggest that a complex intestinal microflora is needed to support oral tolerance development.
Simultaneous Expression and Detection of Multiple Retroviral Constructs in Haematopoietic Cells After Bone Marrow Transplantation
Authors: Nyakeriga A. M. , Djerbi M. , Malinowski M. M. , Grandien A. 
Published: June 2005

AbstractDue to the complexity and redundancy of molecular processes governing the development and function of haematopoietic cells, experimental procedures allowing simultaneous alteration in gene expression of multiple genes in vivo are needed. Here, we describe a protocol allowing for simultaneous transduction of haematopoietic stem cells (HSC) with two different replication incompetent retroviral expression vectors followed by transplantation of lethally irradiated recipient mice. These bicistronic retroviral vectors carried genes for the enhanced green and yellow florescent proteins (EGFP and EYFP) respectively. Spleen cells from reconstituted animals were stained for common lymphocyte and myeloid markers, then analysed on a two‐laser, 488 and 635 nm, flow cytometer equipped with a 510/20‐nm bandpass filter for FL1, a 550/30‐nm bandpass filter for FL2 and a 530‐nm short‐pass dichroic mirror. It was demonstrated that cells expressing EGFP, EYFP or combinations thereof could be distinguished and analysed for staining with PerCP‐ and APC‐conjugated reagents. We found that a sizable proportion of cells (70%) from reconstituted animals expressed EGFP and/or EYFP and that expression of these genes did not affect lymphoid or myeloid development. We also demonstrated that the alternative optical configuration allowed for conventional multiparameter flow cytometric analyses.
CD45RA and RO Isoforms Have Distinct Effects on Cytokine‐ and B‐Cell‐Receptor‐Mediated Signalling in Human B cells
Authors: Mättö M. , Nuutinen U.‐M. , Ropponen A. , Myllykangas K. , Pelkonen J. 
Published: June 2005

AbstractThe common leucocyte antigen, CD45, is widely expressed on the surface of lymphocytes. In T and B cells, CD45 has an important role in the early events of receptor signalling. However, the role of various CD45 isoforms in B‐cell receptor (BCR)‐ and cytokine‐induced signalling and proliferation is still unclear.In the present study, we establish two follicular lymphoma cell lines expressing either CD45RA (HF28RA) or CD45R0 (HF28R0) isoforms. It was observed that the two isoforms had distinct effects on BCR‐ or cytokine‐induced cellular proliferation. BCR stimulation significantly increased the proliferation of HF28R0 cells, in contrast to a decreased proliferation of HF28RA cells. Moreover, proliferation of HF28R0 cells significantly increased after the addition of interleukin‐2 (IL‐2), IL‐4, IL‐6, IL‐10, IL‐12, IL‐13, IL‐15, interferon‐γ and tumour necrosis factor‐α cytokines, whereas most of these cytokines significantly inhibited the proliferation of HF28RA cells. In addition, the cell lines had their individual cytokine mRNA expression profiles after BCR stimulation. We also analysed the effect of CD45 isoforms on intracellular signalling after BCR stimulation. It was found out that the kinetics of ERK1/2 MAP kinase phosphorylation was clearly faster in HF28R0 than in HF28RA cells. The phosphorylation of other analysed MAP kinases or PTKs was very similar in the cell lines.
Expression of the Virulence Factor, BfpA, by Enteropathogenic Escherichia coli is Essential for Apoptosis Signalling but not for NF‐κB Activation in Host Cells
Authors: Melo A. R. , Lasunskaia E. B. , De Almeida C. M. C. , Schriefer A. , Kipnis T. L. , Dias da Silva W. 
Published: June 2005

AbstractLocalized adherence (LA) of enteropathogenic Escherichia coli (EPEC) to epithelial cells results in attaching and effacing of the surface of these cells. LA depends on the gene bfpA, which codes for the BfpA protein. We found that EPEC‐E. coli adherence factor (EAF)(+), expressing BfpA, significantly reduced HeLa cell viability in comparison with EPEC‐EAF(–), as evaluated by the mitochondrial‐dependent succinate dehydrogenase conversion of 3′‐[4,5,‐dimethylthiazol‐2yl]2,5‐diphenyltetrazolium bromide (MTT) to its formazan. Apoptosis accounts for a substantial loss of the cell viability, because the cells incubated with EPEC‐EAF(+) or with cloned BfpA (data not shown), but not with EPEC‐EAF(–), were positive for annexin‐V binding, demonstrated chromatin condensation and nuclei fragmentation and exhibited a high level of caspase‐3 activity. Because the blockade of bacterial cell‐surface‐associated BfpA by anti‐BfpA immunoglobulin (Ig)Y antibody suppressed apoptotic death induced by EPEC‐EAF(+), BfpA may be the trigger for apoptosis. Both EPEC‐EAF(+) and EPEC‐EAF(–), as well as recombinant BfpA (data not shown), activated nuclear factor (NF)‐κB in a similar manner as analysed by the electrophoretic mobility shift assay (EMSA). EMSA supershift analysis demonstrated the presence of p65/RelA in a DNA‐binding complex. In contrast to DNA binding, NF‐κB‐dependent reporter gene transactivation was stimulated more strongly by EPEC B171/EAF(+), suggesting a role for this virulence factor in the regulation of transcriptional activity of NF‐κB. Because suppression of NF‐κB activation by BAY11‐7085, a NF‐κB inhibitor, neither induced apoptosis by itself nor blocked apoptosis induction by EPEC‐EAF(+), it may be suggested that apoptosis is not regulated by the NF‐κB pathway in HeLa cells.
Flow and turbulence structure across the ripple–dune transition: an experiment under mobile bed conditions
Authors: SCHINDLER ROBERT J. , ROBERT ANDRÉ 
Published: June 2005

AbstractCurrent knowledge of flow and turbulent processes acting across the sand bed continuum is still unable to unequivocally explain the mechanism(s) by which ripples become dunes. Understanding has been improved by comparative high‐resolution studies undertaken over fixed bedforms at different stages in the continuum. However, these studies both ignore the role of mobile sediment and do not examine flow structure during the actual transition from ripples to dunes. The aims of the paper are: (i) to describe flow and turbulence characteristics acting above mobile bedforms at several stages across the transition; and (ii) to compare these data with those arising from experiments over fixed ripples and dunes. Laboratory experiments are presented that examine the turbulence structure across seven distinct stages of the transition from ripples to dunes. Single‐point acoustic Doppler velocimeter sampling at three flow heights above a developing mobile boundary was undertaken. Time‐averaged statistics and the instantaneous quadrant record reveal distinct changes in flow structure either side of the change from ripples to dunes. Initially, shear‐related, high‐frequency vortex shedding dominates turbulence production. This increases until two‐dimensional (2D) dunes have formed. Thereafter, turbulence intensities and Reynolds stress decline and three‐dimensional dunes exhibit values found over 2D ripples. This is the result of shear layer dampening which occurs when the topographically‐accelerated downstream velocity increases at a faster rate than flow depth. Activity at reattachment increases due to high velocity fluid imparting high mass and momentum transfer at the bed and/or wake flapping. Suspended sediment may also play a role in turbulence dampening and bed erosion. Ejections dominate over sweeps in terms of event frequency but not magnitude. Strong relationships between inward interactions and sweeps, and ejections and outward interactions, suggest that mass and momentum exchanges are dependent upon activity in all four quadrants. The results contradict the notion present in most physical models that larger bedforms exhibit most shear layer activity. Consequently an improved model for the ripple–dune transition is proposed.
Osmotic regulation of root system architecture
Authors: Deak Karen I. , Malamy Jocelyn 
Published: June 2005

SummaryAlthough root system architecture is known to be highly plastic and strongly affected by environmental conditions, we have little understanding of the underlying mechanisms controlling root system development. Here we demonstrate that the formation of a lateral root from a lateral root primordium is repressed as water availability is reduced. This osmotic‐responsive regulatory mechanism requires abscisic acid (ABA) and a newly identified gene, LRD2. Mutant analysis also revealed interactions of ABA and LRD2 with auxin signaling. Surprisingly, further examination revealed that both ABA and LRD2 control root system architecture even in the absence of osmotic stress. This suggests that the same molecules that mediate responses to environmental cues can also be regulators of intrinsic developmental programs in the root system.
New insights into plant transaldolase
Authors: Caillau Maxime , Paul Quick W. 
Published: June 2005

SummaryThe oxidative pentose phosphate pathway (OPPP) provides plants with important substrates for both primary and secondary metabolism via the oxidation of glucose‐6‐phosphate. The OPPP is also thought to generate large amounts of reducing power to drive various anabolic processes. In animals this major pathway is located within the cytoplasm of cells, but in plants its subcellular compartmentation is far from clear. Although several enzymes of the OPPP were demonstrated to have both cytosolic and plastidic counterparts, there is yet no evidence for a full set of functional enzymes in each compartment. We report here the isolation of two coding sequences from tomato (Lycopersicon esculentum L.) which encode phylogenetically distant sequences (ToTal1 and ToTal2) that putatively encode distinct plastidic TA isoforms. The kinetic characterization of ToTal1 revealed that, unlike other enzymes of the non‐oxidative branch of the OPPP, ToTal1 does not follow a Michaelis–Menten mode of catalysis which has implications for its role in regulating carbon flux between primary and secondary metabolism. TA genes appear to be differentially regulated at the level of gene expression in plant tissues and in response to environmental factors which suggests that TA isoforms have a non‐overlapping role for plant metabolism.
The transcription factor AtGRF5 and the transcription coactivator AN3 regulate cell proliferation in leaf primordia of Arabidopsis thaliana
Authors: Horiguchi Gorou , Kim Gyung‐Tae , Tsukaya Hirokazu 
Published: June 2005

SummaryThe development of the flat morphology of leaf blades is dependent on the control of cell proliferation as well as cell expansion. Each process has a polarity with respect to the longitudinal and transverse axes of the leaf blade. However, only a few regulatory components of these processes have been identified to date. We have characterized two genes from Arabidopsis thaliana: ANGUSTIFOLIA3 (AN3), which encodes a homolog of the human transcription coactivator SYT, and GROWTH‐REGULATING FACTOR5 (AtGRF5), which encodes a putative transcription factor. AN3 is identical to GRF‐INTERACTING FACTOR1 (AtGIF1). The an3 and atgrf5 mutants exhibit narrow‐leaf phenotypes due to decreases in cell number. Conversely, cell proliferation in leaf primordia is enhanced and leaves grow larger than normal when AN3 or AtGRF5 is overexpressed. Both genes are expressed in leaf primordia, and in the yeast two‐hybrid assay, the gene products were found to interact with each other through their N‐terminal domains. These results suggest that AN3 and AtGRF5 act together and are required for the development of appropriate leaf size and shape through the promotion and/or maintenance of cell proliferation activity in leaf primordia.
An important role of phosphatidic acid in ABA signaling during germination in Arabidopsis thaliana
Authors: Katagiri Takeshi , Ishiyama Kanako , Kato Tomohiko , Tabata Satoshi , Kobayashi Masatomo , Shinozaki Kazuo 
Published: June 2005

SummaryPhosphatidic acid (PA) functions as a lipid signaling molecule in plants. Physiological analysis showed that PA triggers early signal transduction events that lead to responses to abscisic acid (ABA) during seed germination. We measured PA production during seed germination and found increased PA levels during early germination. To investigate the role of PA during seed germination, we focused on the PA catabolic enzyme lipid phosphate phosphatase (LPP). LPP catalyzes the conversion of PA to diacylglycerol (DAG). There are 4 LPP genes in the Arabidopsis genome. Among them, AtLPP2 and AtLPP3 are expressed during seed germination. Two AtLPP2 T‐DNA insertional mutants (lpp2‐1 and lpp2‐2) showed hypersensitivity to ABA and significant PA accumulation during germination. Furthermore, double‐mutant analysis showed that ABA‐insensitive 4 (ABI4) is epistatic to AtLPP2 but ABA‐insensitive 3 (ABI3) is not. These results suggest that PA is involved in ABA signaling and that AtLPP2 functions as a negative regulator upstream of ABI4, which encodes an AP2‐type transcription factor, in ABA signaling during germination.
NPH4/ARF7 and ARF19 promote leaf expansion and auxin‐induced lateral root formation
Authors: Wilmoth Jill C. , Wang Shucai , Tiwari Shiv B. , Joshi Atul D. , Hagen Gretchen , Guilfoyle Thomas J. , Alonso Jose M. , Ecker Joseph R. , Reed Jason W. 
Published: June 2005

SummaryAuxin response factors (ARFs) bind auxin response promoter elements and mediate transcriptional responses to auxin. Five of the 22 ARF genes in Arabidopsis thaliana encode ARFs with glutamine‐rich middle domains. Four of these can activate transcription and have been ascribed developmental functions. We show that ARF19, the fifth Q‐rich ARF, also activates transcription. Mutations in ARF19 have little effect on their own, but in combination with mutations in NPH4/ARF7, encoding the most closely related ARF, they cause several phenotypes including a drastic decrease in lateral and adventitious root formation and a decrease in leaf cell expansion. These results indicate that auxin induces lateral roots and leaf expansion by activating NPH4/ARF7 and ARF19. Auxin induces the ARF19 gene, and NPH4/ARF7 and ARF19 together are required for expression of one of the arf19 mutant alleles, suggesting that a positive feedback loop regulates leaf expansion and/or lateral root induction.
The Botany Array Resource: e‐Northerns, Expression Angling, and promoter analyses
Authors: Toufighi Kiana , Brady Siobhan M. , Austin Ryan , Ly Eugene , Provart Nicholas J. 
Published: June 2005

SummaryThe Botany Array Resource provides the means for obtaining and archiving microarray data for Arabidopsis thaliana as well as biologist‐friendly tools for viewing and mining both our own and other's data, for example, from the AtGenExpress Consortium. All the data produced are publicly available through the web interface of the database at http://bbc.botany.utoronto.ca. The database has been designed in accordance with the Minimum Information About a Microarray Experiment [Brazma, A., Hingamp, P., Quackenbush, J. et al. (2001) Minimum information about a microarray experiment (MIAME) – toward standards for microarray data. Nat. Genet.29, 365] convention – all expression data are associated with the corresponding experimental details. The database is searchable and it also provides a set of useful and easy‐to‐use web‐based data‐mining tools for researchers with sophisticated yet understandable output graphics. These include Expression Browser for performing ‘electronic Northerns’, Expression Angler for identifying genes that are co‐regulated with a gene of interest, and Promomer for identifying potential cis‐elements in the promoters of individual or co‐regulated genes.
Species specificity in the adherence of staphylococci to canine and human corneocytes: a preliminary study
Authors: SIMOU CHRISI , HILL PETER B. , FORSYTHE PETER J. , THODAY KEITH L. 
Published: June 2005

Abstract  Staphylococcal pyoderma is rarely contagious between dogs and humans, or humans and dogs. This study investigated the hypothesis that there are species differences in adherence of Staphylococcus intermedius (the most common isolate from dogs) and Staphylococcus aureus (the most common isolate from humans) to canine and human corneocytes. Sheets of corneocytes were collected from the ventral abdomen of 10 dogs and the medial forearm of 10 humans (all healthy and without any history or physical signs of skin disease) using double‐sided tape. Staphylococcus intermedius from a case of canine bacterial pyoderma and a human strain of S. aureus were prepared in phosphate buffered saline (PBS) and applied in duplicate, respectively, to the canine and human corneocyte‐covered tapes using PBS as negative control. After incubation, rinsing, and staining with crystal violet, quantification of the adherent bacteria was carried out blindly by computerized image analysis. Staphylococcus intermedius was found to adhere significantly more to canine corneocytes than S. aureus (P = 0.0006), whereas S. aureus showed greater adherence to human corneocytes than S. intermedius (P < 0.0001). In addition, the pattern of adherence differed between the two organisms, with S. intermedius adhering to the entire surface and S. aureus adhering mainly to the periphery of both canine and human corneocytes. Preference for adherence to these two hosts may explain, in part, why S. intermedius and S. aureus are uncommonly isolated from human and canine skin infections, respectively.