bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double antisense plants lacking ascorbate peroxidase and catalase are less sensitive to oxidative stress than single antisense plants lacking ascorbate peroxidase or catalase
Authors: Rizhsky Ludmila , Hallak‐Herr Elza , Van Breusegem Frank , Rachmilevitch Shimon , Barr Jason E. , Rodermel Steven , Inzé Dirk , Mittler Ron 
Published: March 2003

SummaryThe plant genome is a highly redundant and dynamic genome. Here, we show that double antisense plants lacking the two major hydrogen peroxide‐detoxifying enzymes, ascorbate peroxidase (APX) and catalase (CAT), activate an alternative/redundant defense mechanism that compensates for the lack of APX and CAT. A similar mechanism was not activated in single antisense plants that lacked APX or CAT, paradoxically rendering these plants more sensitive to oxidative stress compared to double antisense plants. The reduced susceptibility of double antisense plants to oxidative stress correlated with suppressed photosynthetic activity, the induction of metabolic genes belonging to the pentose phosphate pathway, the induction of monodehydroascorbate reductase, and the induction of IMMUTANS, a chloroplastic homologue of mitochondrial alternative oxidase. Our results suggest that a co‐ordinated induction of metabolic and defense genes, coupled with the suppression of photosynthetic activity, can compensate for the lack of APX and CAT. In addition, our findings demonstrate that the plant genome has a high degree of plasticity and will respond differently to different stressful conditions, namely, lack of APX, lack of CAT, or lack of both APX and CAT.
The Nod factor‐elicited annexin MtAnn1 is preferentially localised at the nuclear periphery in symbiotically activated root tissues of Medicago truncatula
Authors: De Carvalho‐Niebel Fernanda , Timmers Antonius C. J. , Chabaud Mireille , Defaux‐Petras Annie , Barker David G. 
Published: March 2003

SummaryThe Medicago truncatula MtAnn1 gene, encoding a putative annexin, is transcriptionally activated in root tissues in response to rhizobial Nod factors. To gain further insight into MtAnn1 function during the early stages of nodulation, we have examined in detail both spatio‐temporal gene expression patterns and MtAnn1 activity and localisation in root tissues. Analysis of transgenic Medicago plants expressing a pMtAnn1‐GUS fusion has revealed a novel pattern of transcription in both outer and inner cell layers of the root following either Nod factor‐treatment or rhizobial inoculation. The highest gene expression levels were observed in the endodermis and outer cortex. These transgenic plants also revealed that MtAnn1 expression is associated with lateral root development and cell differentiation in the root apex independent of nodulation. By purifying recombinant MtAnn1 we were able to demonstrate that this plant annexin indeed possesses the calcium‐dependent binding to acidic phospholipids typical of the annexin family. Antisera against recombinant MtAnn1 were then used to show that tissue‐specific localisation of the MtAnn1 protein in Medicago roots matches the pMtAnn1‐GUS expression pattern. Finally, both immunolabelling and in vivo studies using MtAnn1‐GFP reporter fusions have revealed that MtAnn1 is cytosolic and in particular localises to the nuclear periphery in cortical cells activated during the early stages of nodulation. In the light of our findings, we discuss the possible role of this annexin in root tissues responding to symbiotic rhizobial signals.
ABI5 acts downstream of ABI3 to execute an ABA‐dependent growth arrest during germination
Authors: Lopez‐Molina Luis , Mongrand Sébastien , McLachlin Derek T. , Chait Brian T. , Chua Nam‐Hai 
Published: March 2003

SummaryThe development of a germinating embryo into an autotrophic seedling is arrested under conditions of water deficit. This ABA‐mediated developmental checkpoint requires the bZIP transcription factor ABI5. Here, we used abi3‐1, which is also unable to execute this checkpoint, to investigate the relative role of ABI3 and ABI5 in this process. In wild‐type Arabidopsis plants, ABI3 expression and activity parallel those described for ABI5 following stratification. During this process, transcript levels of late embryogenesis genes such as AtEm1 and AtEm6 are also re‐induced, which might be responsible for the acquired osmotic tolerance in germinated embryos whose growth is arrested. ABI5 expression is greatly reduced in abi3‐1 mutants, which has low AtEm1 or AtEm6 expression. Cross complementation experiments showed that 35S‐ABI5 could complement abi3‐1, whereas 35S‐ABI3 cannot complement abi5‐4. These results indicate that ABI5 acts downstream of ABI3 to reactivate late embryogenesis programmes and to arrest growth of germinating embryos. Although ABI5 is consistently located in the nucleus, chromosomal immunoprecipitation (ChIP) experiments revealed that ABA increases ABI5 occupancy on the AtEm6 promoter.
Down‐regulation of DR12, an auxin‐response‐factor homolog, in the tomato results in a pleiotropic phenotype including dark green and blotchy ripening fruit
Authors: Jones Brian , Frasse Pierre , Olmos Enrique , Zegzouti Hicham , Li Zheng Guo , Latché Alain , Pech Jean Claude , Bouzayen Mondher 
Published: March 2003

SummaryFollowing differential screening of gene expression during tomato fruit development, we isolated developmentally regulated (DR) clones, including several putative transcription factors. Based on sequence homology, DR1, DR3, DR4 and DR8 are members of the Aux/IAA family, and DR12 belongs to the auxin response factor (ARF) family of transcription factors. Importantly, mRNA accumulation for the Aux/IAA‐like genes was regulated by ethylene in tomato fruit but not in the leaves, indicating that these putative auxin response components also participate to the ethylene‐dependent regulation of gene expression in a tissue‐specific manner. The functional significance of DR12, the ARF‐like gene, was investigated by cellular biology and reverse genetics approaches. Heterologous protein targeting studies, carried out using a DR12–GFP gene fusion construct, revealed specific nuclear localization of the DR12‐encoded protein, in accordance with its putative function as a transcriptional regulator. Transgenic plants over‐ and under‐expressing DR12 were generated in order to explore the physiological role of the gene. Both antisense and sense co‐suppressed DR12‐inhibited lines displayed a pleiotropic phenotype that included dark‐green immature fruit, unusual cell division in the fruit pericarp, blotchy ripening, enhanced fruit firmness, upward curling leaves and increased hypocotyl and cotyledon growth. While a perturbation of the response to auxin may explain some of the phenotypes, surprisingly, the expression of members of four classes of early auxin‐regulated genes was unaffected in the DR12‐inhibited plants. The involvement of this ARF‐like encoded protein in mediating the auxin response is discussed along with the possibility that it might affect responsiveness to other phytohormones in the tomato.
Parallel recordings of photosynthetic electron transport and K+‐channel activity in single guard cells
Authors: Goh Chang‐Hyo , Dietrich Petra , Steinmeyer Ralf , Schreiber Ulrich , Nam Hong‐Gil , Hedrich Rainer 
Published: March 2003

SummaryStomata open in response to red and blue light. Red light‐induced stomatal movement is mediated by guard cell chloroplasts and related to K+‐uptake into these motor cells. We have combined a new type of microchlorophyll fluorometer with the patch–clamp technique for parallel studies of the photosynthetic electron transport and activity of plasma membrane K+ channels in single guard cell protoplast. In the whole‐cell configuration and presence of ATP in the patch‐pipette, the activity of the K+‐uptake channels remained constant throughout the course of an experiment (up to 30 min) while photosynthetic activity declined to about 50%. In the absence of ATP inward K+ currents declined in a time‐dependent manner. Under these ATP‐free conditions, photosynthetic electron transport was completely blocked within 8 min. ADP together with orthophosphate was able to prevent inhibition of photosynthetic electron transport and run‐down of K+‐channel activity. The results demonstrate that the combination of these two techniques is suited to directly study cytosolic factors as common regulators of photosynthesis and plasma membrane transport within a single‐cell.
The Arabidopsis eukaryotic initiation factor (iso)4E is dispensable for plant growth but required for susceptibility to potyviruses
Authors: Duprat Anne , Caranta Carole , Revers Frédéric , Menand Benoît , Browning Karen S. , Robaglia Christophe 
Published: March 2003

SummaryAn Arabidopsis thaliana line bearing a transposon insertion in the gene coding for the isozyme form of the plant‐specific cap‐binding protein, eukaryotic initiation factor (iso) 4E (eIF (iso) 4E), has been isolated. This mutant line completely lacks both eIF(iso)4E mRNA and protein, but was found to have a phenotype and fertility indistinguishable from wild‐type plants under standard laboratory conditions. In contrast, the amount of the related eIF4E protein was found to increase in seedling extracts. Furthermore, polysome analysis shows that the mRNA encoding eIF4E was being translated at increased levels. Given the known interaction between cap‐binding proteins and potyviral genome‐linked proteins (VPg), this plant line was challenged with two potyviruses, Turnip mosaic virus (TuMV) and Lettuce mosaic virus (LMV) and was found resistant to both, but not to the Nepovirus, Tomato black ring virus (TBRV) and the Cucumovirus, Cucumber mosaic virus (CMV). Together with previous data showing that the VPg–eIF4E interaction is necessary for virus infectivity and upregulates genome amplification, this shows that the eIF4E proteins are specifically recruited for the replication cycle of potyviruses.
The HAT2 gene, a member of the HD‐Zip gene family, isolated as an auxin inducible gene by DNA microarray screening, affects auxin response in Arabidopsis
Authors: Sawa Shinichiro , Ohgishi Maki , Goda Hideki , Higuchi Kanako , Shimada Yukihisa , Yoshida Shigeo , Koshiba Tomokazu 
Published: March 2003

SummaryThe plant hormone, auxin, regulates many aspects of growth and development. Despite its importance, the molecular mechanisms underlying the action of auxin are largely unknown. To gain a more comprehensive understanding of the primary responses to auxin, we analyzed the expression of genes in Arabidopsis seedlings treated with indole‐3‐acetic acid (IAA) for 15 min. We identified a single gene that is downregulated early, and 29 genes that are upregulated early. Several types of typical transcription factors are identified as early upregulated genes, suggesting that auxin signals are mediated by a master set of diverse transcriptional regulators. Of the genes that responded to auxin, the expression of the homeobox gene, HAT2, was induced rapidly. Furthermore, we show that the expression of HAT2 is induced by auxin, but not by other phytohormones. To analyze the function of HAT2 in the plant's response to auxin, we generated 35S::HAT2 transgenic plants. These produced long hypocotyls, epinastic cotyledons, long petioles, and small leaves, which are characteristic of the phenotypes of the auxin‐overproducing mutants, superroot1 (sur1) and superroot2 (sur2). On the other hand, 35S::HAT2 plants showed reduced lateral root elongation, and reduced auxin sensitivity compared to wild‐type plants. Together with the results of RNA blotting and biochemical analyses, these findings suggest that HAT2 plays opposite roles in the shoot and root tissues in regulating auxin‐mediated morphogenesis.
Cloning and functional expression of alkaline α‐galactosidase from melon fruit: similarity to plant SIP proteins uncovers a novel family of plant glycosyl hydrolases
Authors: Carmi Nir , Zhang Genfa , Petreikov Marina , Gao Zhifang , Eyal Yoram , Granot David , Schaffer Arthur A. 
Published: March 2003

SummaryRaffinose and stachyose are ubiquitous galactosyl‐sucrose oligosaccharides in the plant kingdom which play major roles, second only to sucrose, in photoassimilate translocation and seed carbohydrate storage. These sugars are initially metabolised by α‐galactosidases (α‐gal). We report the cloning and functional expression of the first genes, CmAGA1 and CmAGA2, encoding for plant α‐gals with alkaline pH optima from melon fruit (Cucumis melo L.), a raffinose and stachyose translocating species. The alkaline α‐gal genes show very high sequence homology with a family of undefined ‘seed imbibition proteins’ (SIPs) which are present in a wide range of plant families. In order to confirm the function of SIP proteins, a representative SIP gene, from tomato, was expressed and shown to have alkaline α‐gal activity. Phylogenetic analysis based on amino acid sequences shows that the family of alkaline α‐gals shares little homology with the known prokaryotic and eukaryotic α‐gals of glycosyl hydrolase families 27 and 36, with the exception of two cross‐family conserved sequences containing aspartates which probably function in the catalytic step. This previously uncharacterised, plant‐specific α‐gal family of glycosyl hydrolases, with optimal activity at neutral‐alkaline pH likely functions in key processes of galactosyl‐oligosaccharide metabolism, such as during seed germination and translocation of RFO photosynthate.
Allene oxide cyclase dependence of the wound response and vascular bundle‐specific generation of jasmonates in tomato – amplification in wound signalling
Authors: Stenzel Irene , Hause Bettina , Maucher Helmut , Pitzschke Andrea , Miersch Otto , Ziegler Jörg , Ryan Clarence A. , Wasternack Claus 
Published: March 2003

SummaryThe allene oxide cyclase (AOC)‐catalyzed step in jasmonate (JA) biosynthesis is important in the wound response of tomato. As shown by treatments with systemin and its inactive analog, and by analysis of 35S::prosysteminsense and 35S::prosysteminantisense plants, the AOC seems to be activated by systemin (and JA) leading to elevated formation of JA. Data are presented on the local wound response following activation of AOC and generation of JA, both in vascular bundles. The tissue‐specific occurrence of AOC protein and generation of JA is kept upon wounding or other stresses, but is compromised in 35S::AOCsense plants, whereas 35S::AOCantisense plants exhibited residual AOC expression, a less than 10% rise in JA, and no detectable expression of wound response genes. The (i) activation of systemin‐dependent AOC and JA biosynthesis occurring only upon substrate generation, (ii) the tissue‐specific occurrence of AOC in vascular bundles, where the prosystemin gene is expressed, and (iii) the tissue‐specific generation of JA suggest an amplification in the wound response of tomato leaves allowing local and rapid defense responses.
AtBXL1, a novel higher plant (Arabidopsis thaliana) putative beta‐xylosidase gene, is involved in secondary cell wall metabolism and plant development
Authors: Goujon Thomas , Minic Zoran , El Amrani Abdelhak , Lerouxel Olivier , Aletti Estelle , Lapierre Catherine , Joseleau Jean‐Paul , Jouanin Lise 
Published: March 2003

SummaryTo investigate mechanisms involved in cell wall development, an Arabidopsis T‐DNA insertion mutant collection was screened to identify mutants with beta‐glucuronidase fusion gene expression in tissues undergoing secondary cell wall thickening. This promoter‐trapping strategy allowed the isolation of a transformant containing the GUS coding sequence inserted 700 bp upstream of the ATG of a putative beta‐xylosidase gene. The transformant has no phenotype as the expression of the gene was not disrupted by the insertion. The analysis of the predicted protein, AtBXL1, suggests its targeting to the extracellular matrix and its involvement in cell wall metabolism through a putative activity towards xylans. The 2‐kb promoter sequence of AtBXL1 was fused to the GUS coding sequence and introduced into wild‐type Arabidopsis thaliana. GUS expression was shown to be restricted to tissues undergoing secondary cell wall formation. Beta‐xylosidase activity was associated with the cell wall‐enriched fraction of different organs of wild‐type plants. The level of activity correlates with transcript accumulation of AtBXL1 and other AtBXL1‐related genes. Transgenic plants expressing the AtBXL1 cDNA in antisense orientation were generated. Lines exhibiting the highest decrease in AtBXL1 transcript accumulation and beta‐xylosidase activity had phenotypic alterations. This newly identified gene is proposed to be involved in secondary cell wall hemicellulose metabolism and plant development.
Module‐specific regulation of the β‐phaseolin promoter during embryogenesis
Authors: Chandrasekharan Mahesh B. , Bishop Kenneth J. , Hall Timothy C. 
Published: March 2003

SummaryThephaspromoter displays stringent spatial regulation, being very highly expressed during embryogenesis and completely silent during all phases of vegetative development in bean,Phaseolus vulgaris. This pattern is maintained in transgenic tobacco and, as shown here,Arabidopsis. Dimethyl sulphatein vivofootprinting analyses revealed that over 20cis‐elements within the proximal 295 bp of thephaspromoter are protected by factor binding in seed tissues whereas none are bound in leaves. The hypothesis that this complex profile represents a summation of several module (cotyledon, hypocotyl, and radicle)‐specific factor–DNA interactions has been explored by the incorporation of site‐directed substitution mutations into 10 locations within the −295phaspromoter. Only 2.6% of−295phaspromoter activity remained after mutation of theG‐box; theCCAAATbox, theE‐box and theRYelements were also found to mediate high levels of expression in embryos. Whereas theCACAelement has dual positive and negative regulatory roles, thevicilinbox was identified as a strong negative regulatory element. The proximal (−70 to −64)RYmotif was found to bestow expression in the hypocotyl while all theRYelements contribute to expression in cotyledons but not to vascular tissue expression during embryogenesis.RYelements at positions −277 to −271, −260 to −254, and −237 to −231 were found to orchestrate radicle‐specific repression. TheG‐box appears to be the functional abscisic acid responsive element and theE‐site may be a coupling element. The results substantiate the concept that autarkicalcis‐element functions generate modular patterning during embryogenesis. They also reflect the existence of both redundancy and hierarchy incis–element interactions. Importantly, the virtually identical expression patterns observed for the two distantly related plants studied argue strongly for the generality of function for the observed factor–element interactions.
The impact of a 10‐year audit cycle on blood usage in a district general hospital
Authors: James R. M. , Brown S. , Parapia L. A. , Williams A. T. 
Published: March 2003

. As clinical governance moves from concept to practice, it is emerging as a realistic strategy to promote and improve quality within the National Health Service, as well as satisfying the demand for external accountability. In the context of blood transfusion, the area of responsibility encompasses product liability, as well as efficient use of blood as a resource and transfusion as an appropriate clinical response. Clinical governance may be a modern catch phrase, but the principles it enshrines have long been established within blood transfusion, and in other aspects of haematology. Here, an audit cycle comprising four audits over a 10‐year period to monitor the use of cross‐matched blood in a large district general hospital is described.Initially, blood use was considered by hospital site, and by the surgical procedure for which it was requested. Later, the scope of the audit was expanded to consider usage by individual consultant. A standard of efficient use of cross‐matched blood was taken to be a cross‐match to transfusion ratio of < 1·5.The information was reviewed by the hospital transfusion committee, who have a key role in co‐ordinating and assessing the practice of transfusion within a hospital. In this hospital, audit has been one of the main tools for improving practice, in particular by enabling the implementation and continuous revision of a maximum blood order schedule.Further, as the process of audit has developed, problem areas have been highlighted, and strategies to improve usage have been brought in with encouraging results. The audit is now being expanded again to include a greater focus on usage of cross‐matched blood in the nonsurgical setting.
An unusual case of hyperkalaemia‐induced cardiac arrest in a paediatric patient during transfusion of a ‘fresh’ 6‐day‐old blood unit
Authors: Baz E. M. K. , Kanazi G. E. , Mahfouz R. A. R. , Obeid M. Y. 
Published: March 2003

Summary A well‐recognized complication of the transfusion of red blood cells (RBCs) is hyperkalaemia. This occurs in paediatric or adult patients receiving massive transfusion and can lead to cardiac arrest. Hyperkalaemia may follow the transfusion of ‘stored’ RBCs and/or haemolysed units, and depends on the quantity and rate of transfusion. We report on an unusual case of hyperkalaemia‐induced cardiac arrest during transfusion of a ‘fresh’ blood unit. A 62‐day‐old baby girl was scheduled for a construction of a Blalock–Taussig shunt, after the completion of anastomosis, and upon release of vascular control, there was bleeding at the anastomotic site that was controlled with a suture placement. To compensate for the blood loss, a stat order was given for a push of 120 mL of RBCs over 10 min through the inferior vena cava central line. The blood unit was 6 days old and had been gamma‐irradiated 48 h earlier. Shortly after the transfusion, the patient's electrocardiogram showed changes typical of hyperkalaemia; she then went into cardiac asystole. The blood unit potassium concentration was 55·3 mmol L−1, which flushed the atrioventricular node during transfusion.This is the first report of a high potassium level found in a ‘fresh’, less than 7 days old, nonhaemolysed RBC blood unit. The high concentration of potassium in this unit seems to be due to accelerated alterations of the RBC sodium/potassium adenosine triphosphatase pump (Na+/K+ pump), resulting in the release of intracellular potassium. This early and severe alteration of the pump and the unusually high potassium level may be due to as yet unexplained causes, warranting awareness, future investigation and routine saline washing of ‘fresh’ RBCs for paediatric patients who are candidates for central line transfusion.
Yellow fever vaccination during pregnancy and spontaneous abortion: a case‐control study
Authors: De A. Nishioka Sérgio , Nunes‐Ara£jo F. R. F. , Pires Waldely P. , Silva Flávia A. , Costa Hégena L. 
Published: March 2003

objective

To assess a possible association between Yellow fever (YF) vaccine (inadvertently) administered during early pregnancy and spontaneous abortion.method  A hospital‐based case‐control study conducted in a Brazilian town after a YF vaccine campaign that followed an epidemic of dengue. The study included 39 women who attended a university hospital with spontaneous abortion (cases) and 74 pregnant women attending the antenatal clinic of that hospital (controls).results  The crude odds ratio (relative risk estimate) of this association was 2.49, which dropped to 2.29 (95% CI 0.65–8.03) when adjusted for several confounders by multiple logistic regression. Dengue and exposure to organophosphate insecticide fogging during pregnancy were not associated with spontaneous abortion.conclusion  This study, although small and with low power, provides some evidence that women vaccinated with YF vaccine during early pregnancy have an increased risk of having spontaneous abortion. Based on these findings a sensible recommendation should be to avoid YF vaccination of pregnant women unless their risk of acquiring YF outweighs the risk of vaccine‐related abortion.