bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of PPS3 Phosphorylated by Elicitor-Responsive Mitogen-Activated Protein Kinases in the Regulation of Plant Cell Death
Authors: Katou Shinpei , Yoshioka Hirofumi , Kawakita Kazuhito , Rowland Owen , Jones Jonathan D.G. , Mori Hitoshi , Doke Noriyuki 
Published: November 2005

Abstract
Mitogen-activated protein kinase (MAPK) cascades play pivotal roles in plant innate immunity. Overexpression of StMEK1DD, a constitutively active MAPK kinase that activates salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK), provokes hypersensitive response-like cell death in Nicotiana benthamiana. Here we purified a 51-kD MAPK, which was activated in potato (Solanum tuberosum) tubers treated with hyphal wall elicitor of a plant pathogen, and isolated the cDNA designated StMPK1. The deduced amino acid sequence of the StMPK1 showed strong similarity to stress-responsive MAPKs, such as tobacco (Nicotiana tabacum) SIPK and Arabidopsis (Arabidopsis thaliana) AtMPK6. To investigate the downstream signaling of StMPK1, we identified several proteins phosphorylated by StMPK1 (PPSs) using an in vitro expression cloning method. To dissect the biological function of PPSs in the plant defense, we employed virus-induced gene silencing (VIGS) in N. benthamiana. VIGS of NbPPS3 significantly delayed cell death induced by the transient expression of StMEK1DD and treatment with hyphal wall elicitor. Furthermore, the mobility shift of NbPPS3 on SDS-polyacrylamide gel was induced by transient expression of StMEK1DD. The mobility shift of NbPPS3 induced by StMEK1DD was not compromised by VIGS of WIPK or SIPK alone, but drastically reduced by the silencing of both WIPK and SIPK. This work strongly supports the idea that PPS3 is a physiological substrate of StMPK1 and is involved in cell death activated by a MAPK cascade.
Pathogen-Responsive Expression of Glycosyltransferase Genes UGT73B3 and UGT73B5 Is Necessary for Resistance to Pseudomonas syringae pv tomato in Arabidopsis
Authors: Langlois-Meurinne Mathilde , Gachon Claire M.M. , Saindrenan Patrick 
Published: November 2005

Abstract
The genome sequencing of Arabidopsis (Arabidopsis thaliana) has revealed that secondary metabolism plant glycosyltransferases (UGTs) are encoded by an unexpectedly large multigenic family of 120 members. Very little is known about their actual function in planta, in particular during plant pathogen interactions. Among them, members of the group D are of particular interest since they are related to UGTs involved in stress-inducible responses in other plant species. We provide here a detailed analysis of the expression profiles of this group of Arabidopsis UGTs following infection with Pseudomonas syringae pv tomato or after treatment with salicylic acid, methyljasmonate, and hydrogen peroxide. Members of the group D displayed distinct induction profiles, indicating potential roles in stress or defense responses notably for UGT73B3 and UGT73B5. Analysis of UGT expression in Arabidopsis defense-signaling mutants further revealed that their induction is methyljasmonate independent, but partially salicylic acid dependent. T-DNA tagged mutants (ugt73b3 and ugt73b5) exhibited decreased resistance to P. syringae pv tomato-AvrRpm1, indicating that expression of the corresponding UGT genes is necessary during the hypersensitive response. These results emphasize the importance of plant secondary metabolite UGTs in plant-pathogen interactions and provide foundation for future understanding of the exact role of UGTs during the hypersensitive response.
Cell Expansion and Endoreduplication Show a Large Genetic Variability in Pericarp and Contribute Strongly to Tomato Fruit Growth
Authors: Cheniclet Catherine , Rong Wen Ying , Causse Mathilde , Frangne Nathalie , Bolling Laurence , Carde Jean-Pierre , Renaudin Jean-Pierre 
Published: November 2005

Abstract
Postanthesis growth of tomato (Solanum lycopersicon) as of many types of fruit relies on cell division and cell expansion, so that some of the largest cells to be found in plants occur in fleshy fruit. Endoreduplication is known to occur in such materials, which suggests its involvement in cell expansion, although no data have demonstrated this hypothesis as yet. We have analyzed pattern formation, cell size, and ploidy in tomato fruit pericarp. A first set of data was collected in one cherry tomato line throughout fruit development. A second set of data was obtained from 20 tomato lines displaying a large weight range in fruit, which were compared as ovaries at anthesis and as fully grown fruit at breaker stage. A remarkable conservation of pericarp pattern, including cell layer number and cell size, is observed in all of the 20 tomato lines at anthesis, whereas large variations of growth occur afterward. A strong, positive correlation, combining development and genetic diversity, is demonstrated between mean cell size and ploidy, which holds for mean cell diameters from 10 to 350 μm (i.e. a 32,000-times volume variation) and for mean ploidy levels from 3 to 80 C. Fruit weight appears also significantly correlated with cell size and ploidy. These data provide a framework of pericarp patterning and growth. They strongly suggest the quantitative importance of polyploidy-associated cell expansion as a determinant of fruit weight in tomato.
Sensing of Inorganic Carbon Limitation in Synechococcus PCC7942 Is Correlated with the Size of the Internal Inorganic Carbon Pool and Involves Oxygen
Authors: Woodger Fiona J. , Badger Murray R. , Price G. Dean 
Published: November 2005

Abstract
Freshwater cyanobacteria are subjected to large seasonal fluctuations in the availability of nutrients, including inorganic carbon (Ci). We are interested in the regulation of the CO2-concentrating mechanism (CCM) in the model freshwater cyanobacterium Synechococcus sp. strain PCC7942 in response to Ci limitation; however, the nature of Ci sensing is poorly understood. We monitored the expression of high-affinity Ci-transporter genes and the corresponding induction of a high-affinity CCM in Ci-limited wild-type cells and a number of CCM mutants. These genotypes were subjected to a variety of physiological and pharmacological treatments to assess whether Ci sensing might involve monitoring of fluctuations in the size of the internal Ci pool or, alternatively, the activity of the photorespiratory pathway. These modes of Ci sensing are congruent with previous results. We found that induction of a high-affinity CCM correlates most closely with a depletion of the internal Ci pool, but that full induction of this mechanism also requires some unresolved oxygen-dependent process.
Subcellular Localization and Light-Regulated Expression of Protoporphyrinogen IX Oxidase and Ferrochelatase in Chlamydomonas reinhardtii
Authors: van Lis Robert , Atteia Ariane , Nogaj Luiza A. , Beale Samuel I. 
Published: November 2005

Abstract
Protoporphyrinogen IX oxidase (PPO) catalyzes the last common step in chlorophyll and heme synthesis, and ferrochelatase (FeC) catalyzes the last step of the heme synthesis pathway. In plants, each of these two enzymes is encoded by two or more genes, and the enzymes have been reported to be located in the chloroplasts or in the mitochondria. We report that in the green alga Chlamydomonas reinhardtii, PPO and FeC are each encoded by a single gene. Phylogenetic analysis indicates that C. reinhardtii PPO and FeC are most closely related to plant counterparts that are located only in chloroplasts. Immunoblotting results suggest that C. reinhardtii PPO and FeC are targeted exclusively to the chloroplast, where they are associated with membranes. These results indicate that cellular needs for heme in this photosynthetic eukaryote can be met by heme that is synthesized in the chloroplast. It is proposed that the multiplicity of genes for PPO and FeC in higher plants could be related to differential expression in differently developing tissues rather than to targeting of different gene products to different organelles. The FeC content is higher in C. reinhardtii cells growing in continuous light than in cells growing in the dark, whereas the content of PPO does not significantly differ in light- and dark-grown cells. In cells synchronized to a light/dark cycle, the level of neither enzyme varied significantly with the phase of the cycle. These results indicate that heme synthesis is not directly regulated by the levels of PPO and FeC in C. reinhardtii.
Expression Profile of Two Storage-Protein Gene Families in Hexaploid Wheat Revealed by Large-Scale Analysis of Expressed Sequence Tags
Authors: Kawaura Kanako , Mochida Keiichi , Ogihara Yasunari 
Published: November 2005

Abstract
To discern expression patterns of individual storage-protein genes in hexaploid wheat (Triticum aestivum cv Chinese Spring), we analyzed comprehensive expressed sequence tags (ESTs) of common wheat using a bioinformatics technique. The gene families for α/β-gliadins and low molecular-weight glutenin subunit were selected from the EST database. The alignment of these genes enabled us to trace the single nucleotide polymorphism sites among both genes. The combinations of single nucleotide polymorphisms allowed us to assign haplotypes into their homoeologous chromosomes by allele-specific PCR. Phylogenetic analysis of these genes showed that both storage-protein gene families rapidly diverged after differentiation of the three genomes (A, B, and D). Expression patterns of these genes were estimated based on the frequencies of ESTs. The storage-protein genes were expressed only during seed development stages. The α/β-gliadin genes exhibited two distinct expression patterns during the course of seed maturation: early expression and late expression. Although the early expression genes among the α/β-gliadin and low molecular-weight glutenin subunit genes showed similar expression patterns, and both genes from the D genome were preferentially expressed rather than those from the A or B genome, substantial expression of two early expression genes from the A genome was observed. The phylogenetic relationships of the genes and their expression patterns were not correlated. These lines of evidence suggest that expression of the two storage-protein genes is independently regulated, and that the α/β-gliadin genes possess novel regulation systems in addition to the prolamin box.
A novel 3‐dimensional culture system as an in vitro model for studying oral cancer cell invasion
Authors: Duong Hai S. , Le Anh D. , Zhang Qunzhou , Messadi Diana V. 
Published: November 2005

SummaryTissue microenvironment plays a critical role in tumour growth and invasion. This study established a novel 3‐dimensional (3‐D) cell invasion model for direct microscopic observation of oral cancer cell invasion into the underlying basement membrane and connective tissue stroma. A multilayer cell construct was developed using the OptiCell chamber, consisting of a lower layer of oral mucosa fibroblasts embedded in collagen gel and an overlaying upper layer of oral cancer cells. The two layers are separated by a basement membrane composed of reconstituted extracellular matrix. To verify the applicability of the cell invasion model, multilayer cell constructs of oral squamous cell carcinoma and oral mucosal fibroblasts were exposed to extrinsic urokinase‐type plasminogen activator (uPA) or plasminogen activator inhibitor (PAI‐1), which are known effectors of cell migration. In addition, the constructs were exposed to both normoxic and hypoxic culture conditions. Microscopic study showed that the presence of uPA enhanced cell invasion, while PAI‐1 inhibited cell migration. Western blot and zymographic analysis demonstrated that hypoxia up‐regulated uPA and matrix metalloproteinases (MMPs) expression and activity; conversely, PAI‐1 level was down‐regulated in response to hypoxic challenge as compared to normoxic condition. Our results indicated that the novel 3‐D invasion model could serve as an excellent in vitro model to study cancer cell invasion and to test conditions or mediators of cellular migration.
Abnormal expression of bcl‐2 and bax in rat tongue mucosa during the development of squamous cell carcinoma induced by 4‐nitroquinoline 1‐oxide
Authors: Ribeiro Daniel A. , Salvadori Daisy M. F. , Marques Mariângela E. A. 
Published: November 2005

Summary4‐Nitroquinoline 1‐oxide (4NQO)‐induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the expression of bcl‐2 and bax during tongue carcinogenesis induced by 4NQO. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Although no histological changes were induced in the epithelium after 4 weeks of carcinogen exposure, bcl‐2 and bax were over‐expressed (P < 0.01) in all layers of the ‘normal’ epithelium. The expression levels were the same in all layers of epithelium for both the antibodies used (bcl‐2 or bax). In dysplastic lesions at 12 weeks following carcinogen administration, the levels of bcl‐2 and bax expression did not increase when compared to negative control with the immunoreactivity for bcl‐2 being restricted to the superficial layer of epithelium. In well‐differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, bcl‐2 was expressed in some cells of tumour islands. On the other hand, immunostaining for bax was widely observed at the tumour nests. The labelling index for bcl‐2 and bax showed an increase (P < 0.05) after only 4 weeks of 4NQO administration. In conclusion, our results suggest that abnormalities in the apoptosis pathways are associated with the development of persistent clones of mutated‐epithelial cells in the oral mucosa. Bcl‐2 and bax expression appears to be associated with a risk factor in the progression of oral cancer.
Neoplastic transformation and angiogenesis in the thymus of transgenic mice expressing SV40 T and t antigen under an l‐pyruvate kinase promoter (SV12 mice)
Authors: Nabarra Bernadette , Pontoux Christiane , Godard Cecile , Osborne‐Pellegrin Mary , Ezine Sophie 
Published: November 2005

SummaryUsing several techniques, we have assessed morphological characteristics of a malignant thymic tumour in SV12 transgenic (Tg) mice expressing SV40 T and t antigens under control of an L‐PK promoter. We describe the development of a carcinoma originating from thymic hyperplasia and followed by the formation of a benign tumour composed chiefly of medullary epithelial cells expressing the transgene and of lymphocytes, a pathology very rarely reported in mice. Our study of the SV12 Tg mice represents the first description of a model of a pure malignant thymic tumour associated with extensive angiogenesis maintained in numerous descendants. The formation of a large tumoral neovascular network, observed here, has never been described in human and/or experimental thymic tumours. Tumoral transformation and angiogenesis are demonstrated by immunolabelling with antibodies against various cytokeratins (CKs) of different molecular weights, vascular endothelial cell markers and VEGF/receptor‐2 (Flk‐1) present on the neovascular endothelial cells. Different points raised by the originality of this model are discussed. These include the medullary nature of the cells expressing the SV40 transgene and their relationship with the tumoral development. The subset of different molecular weight CK components and their modifications are also considered, as well as the presence of type IV epithelial cells, progenitors of medullary epithelial cells. Finally, the cell signals involved in angiogenesis and the possible action of an angiogenic factor, probably secreted by the tumoral cells themselves, are discussed.
The haemotoxicity of mitomycin in a repeat dose study in the female CD‐1 mouse
Authors: Molyneux Gemma , Gibson Frances M. , Gordon‐Smith Edward C. , Pilling Andrew M. , Liu Kai Chiu , Rizzo Sian , Sulsh Susan , Turton John A. 
Published: November 2005

SummaryMitomycin (MMC), like many antineoplastic drugs, induces a predictable, dose‐related, bone marrow depression in man and laboratory animals; this change is generally reversible. However, there is evidence that MMC may also cause a late‐stage or residual bone marrow injury. The present study in female CD‐1 mice investigated the haematological and bone marrow changes induced by MMC in a repeat dose study lasting 50 days. Control and MMC‐treated mice were dosed intraperitoneally on eight occasions over 18 days with vehicle, or MMC at 2.5 mg/kg, autopsied (n = 6–12) at 1, 7, 14, 28, 42 and 50 days after the final dose and haematological changes investigated. Femoral nucleated bone marrow cell counts and levels of apoptosis were also evaluated and clonogenic assays carried out; serum levels of FLT3 ligand (FL) were assessed. At day 1 post‐dosing, MMC induced significant reductions in RBC, Hb and haematocrit (HCT) values, and there were decreases in reticulocyte, platelet, and femoral nucleated cell counts (FNCC); neutrophil, lymphocyte and monocyte values were also significantly reduced. On days 7 and 14 post‐dosing, all haematological parameters showed evidence of a return towards normal values, but at these times, and at day 28, values for RBC and FNCC remained significantly reduced in comparison with controls. At days 42 and 50 post‐dosing, many haematological parameters in MMC‐treated mice had returned to control levels; however, there remained evidence of late‐stage effects on RBC, Hb and HCT values, and FNCC also continued to be significantly decreased. Results for granulocyte‐macrophage colony‐forming units and erythroid colonies showed a profound decrease immediately post‐dosing, but a return to normal values was evident at day 50. Serum FL concentrations demonstrated very significant increases in the immediate post‐dosing period, but a return to normal was seen at day 50 post‐dosing; a relatively similar pattern was seen in the number of apoptotic femoral marrow nucleated cells. The histopathological examination of kidney tissues from MMC animals at day 42 and 50 post‐dosing showed evidence of hydronephrosis with cortical glomerular/tubular atrophy and degeneration. It is therefore concluded that MMC administered on eight occasions over 18 days to female CD‐1 mice at 2.5 mg/kg induced profound changes in haematological and bone marrow parameters in the immediate post‐dosing period with a return to normal levels at day 50 post‐dosing; however, there was evidence of mild but significant late‐stage/residual effects on RBC and FNCC, and on cells of the erythroid lineage in the bone marrow.
Comparison of enhancing effects of different goitrogen treatments in combination with β‐estradiol‐3‐benzoate for establishing a rat two‐stage thyroid carcinogenesis model to detect modifying effects of estrogenic compounds
Authors: Takizawa Tamotsu , Imai Toshio , Ueda Makoto , Onodera Hiroshi , Hirose Masao 
Published: November 2005

With the aim of establishing a sensitive model for the detection of weak effects of endocrine disrupting chemicals on thyroid carcinogenesis, thyrotrophic and tumor‐promoting influences of β‐estradiol‐3‐benzoate (EB) in combination with representative antithyroidal agents (goitrogens), sulfadimethoxine (SDM), propylthiouracil (PTU), potassium perchlorate (PPC), iopanoic acid (IOP) or an iodine‐deficient diet were evaluated in a short‐term (7‐day) experiment without N‐bis(2‐hydroxypropyl)nitrosamine (DHPN) initiation and a long‐term (30‐week) experiment with DHPN initiation in ovariectomized F344 rats. In the short‐term experiment, the most remarkable thyrotrophic effects were found in the PTU‐treated group, followed by the SDM and PPC cases. EB treatment alone caused slight increases in thyroidal weights but no apparent morphological changes. Concomitant treatment with EB and antithyroidal agents enhanced the changes in thyroid weights, histopathological findings and/or serum thyroid hormone levels in the SDM (30 and 100 p.p.m), PTU (5 and 30 p.p.m) and PPC (100 p.p.m), IOP (30 and 100 mg/kg) or iodine‐deficient diet groups. In the long‐term experiment after DHPN initiation, EB alone slightly increased small numbers of animals with follicular hyperplasias, adenomas and adenocarcinomas. Simultaneous treatment with antithyroidal chemicals was associated with an increase in the incidences of focal hyperplasias, adenomas and/or adenocarcinomas. The enhancement was most remarkable with PTU (5 p.p.m), followed by PTU (2 p.p.m), SDM (100 p.p.m) and PPC (100 p.p.m). The results showed that EB has only a marginal promoting effect on DHPN‐induced rat thyroid carcinogenesis and that antithyroidal chemicals, particularly PTU, are effective as copromoting agents. (Cancer Sci2005)
The performance of STA‐Liatest D‐dimer assay in out‐patients with suspected pulmonary embolism
Authors: Ghanima W. , Abdelnoor M. , Mowinckel M.‐C. , Sandset P. M. 
Published: November 2005

SummarySeveral studies have shown that d‐dimer can reliably rule out pulmonary embolism (PE) in out‐patients. However, various assays have different sensitivities and specificities to detect thrombosis. Our aim was to evaluate the performance of STA‐Liatest D‐Di in out‐patients referred for suspected PE in a prospective outcome study. 495 consecutive patients referred to Østfold Hospital Trust‐Fredrikstad, Norway for suspected PE between February 2002 and December 2003, were recruited in a study evaluating a decision‐based algorithm combining clinical probability (CP), d‐dimer, and multi‐slice computer tomography (MSCT). d‐dimer was performed as a first step test. No further testing was carried out in patients with d‐dimer ≤0·4 mg/l and low/intermediate CP. The remaining patients proceeded to MSCT. All patients were followed up for 3 months to assess the 3‐month thromboembolic risk. The final cohort consisted of 432 patients. PE was diagnosed in 102 (23%) patients. At a d‐dimer cut‐off point of 0·4 mg/l the tests had the highest sensitivity (100%) and specificity (36%). It safely ruled out PE in 120 (28%) patients. Kappa‐coefficients for comparisons versus VIDAS and Asserachrom showed good concordance. STA‐Liatest is a reliable and effective assay that can safely rule out PE in out‐patients with a performance comparable with that of enzyme‐linked immunosorbent assay‐based d‐dimer levels.