bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for a Direct Link between Glutathione Biosynthesis and Stress Defense Gene Expression in Arabidopsis[W]
Authors: Ball Louise , Accotto Gian-Paolo , Bechtold Ulrike , Creissen Gary , Funck Dietmar , Jimenez Ana , Kular Baldeep , Leyland Nicola , Mejia-Carranza Jaime , Reynolds Helen , Karpinski Stanislaw , Mullineaux Philip M. 
Published: September 2004

AbstractThe mutant regulator of APX2 1-1 (rax1-1) was identified in Arabidopsis thaliana that constitutively expressed normally photooxidative stress-inducible ASCORBATE PEROXIDASE2 (APX2) and had ≥50% lowered foliar glutathione levels. Mapping revealed that rax1-1 is an allele of γ-GLUTAMYLCYSTEINE SYNTHETASE 1 (GSH1), which encodes chloroplastic γ-glutamylcysteine synthetase, the controlling step of glutathione biosynthesis. By comparison of rax1-1 with the GSH1 mutant cadmium hypersensitive 2, the expression of 32 stress-responsive genes was shown to be responsive to changed glutathione metabolism. Under photo-oxidative stress conditions, the expression of a wider set of defense-related genes was altered in the mutants. In wild-type plants, glutathione metabolism may play a key role in determining the degree of expression of defense genes controlled by several signaling pathways both before and during stress. This control may reflect the physiological state of the plant at the time of the onset of an environmental challenge and suggests that changes in glutathione metabolism may be one means of integrating the function of several signaling pathways.
A High-Resolution Transcript Profile across the Wood-Forming Meristem of Poplar Identifies Potential Regulators of Cambial Stem Cell Identity[W]
Authors: Schrader Jarmo , Nilsson Jeanette , Mellerowicz Ewa , Berglund Anders , Nilsson Peter , Hertzberg Magnus , Sandberg Göran 
Published: September 2004

AbstractPlant growth is the result of cell proliferation in meristems, which requires a careful balance between the formation of new tissue and the maintenance of a set of undifferentiated stem cells. Recent studies have provided important information on several genetic networks responsible for stem cell maintenance and regulation of cell differentiation in the apical meristems of shoots and roots. Nothing, however, is known about the regulatory networks in secondary meristems like the vascular cambium of trees. We have made use of the large size and highly regular layered organization of the cambial meristem to create a high-resolution transcriptional map covering 220 μm of the cambial region of aspen (Populus tremula). Clusters of differentially expressed genes revealed substantial differences in the transcriptomes of the six anatomically homogenous cell layers in the meristem zone. Based on transcriptional and anatomical data, we present a model for the position of the stem cells and the proliferating mother cells in the cambial zone. We also provide sets of marker genes for different stages of xylem and phloem differentiation and identify potential regulators of cambial meristem activity. Interestingly, analysis of known regulators of apical meristem development indicates substantial similarity in regulatory networks between primary and secondary meristems.
Control of Plant Trichome Development by a Cotton Fiber MYB Gene[W]
Authors: Wang Shui , Wang Jia-Wei , Yu Nan , Li Chun-Hong , Luo Bin , Gou Jin-Ying , Wang Ling-Jian , Chen Xiao-Ya 
Published: September 2004

AbstractCotton (Gossypium spp) plants produce seed trichomes (cotton fibers) that are an important commodity worldwide; however, genes controlling cotton fiber development have not been characterized. In Arabidopsis thaliana the MYB gene GLABRA1 (GL1) is a central regulator of trichome development. Here, we show that promoter of a cotton fiber gene, RD22-like1 (RDL1), contains a homeodomain binding L1 box and a MYB binding motif that confer trichome-specific expression in Arabidopsis. A cotton MYB protein GaMYB2/Fiber Factor 1 transactivated the RDL1 promoter both in yeast and in planta. Real-time PCR and in situ analysis showed that GaMYB2 is predominantly expressed early in developing cotton fibers. After transferring into Arabidopsis, GL1::GaMYB2 rescued trichome formation of a gl1 mutant, and interestingly, 35S::GaMYB2 induced seed-trichome production. We further demonstrate that the first intron of both GL1 and GaMYB2 plays a role in patterning trichomes: it acts as an enhancer in trichome and a repressor in nontrichome cells, generating a trichome-specific pattern of MYB gene expression. Disruption of a MYB motif conserved in intron 1 of GL1, WEREWOLF, and GaMYB2 genes affected trichome production. These results suggest that cotton and Arabidopsis use similar transcription factors for regulating trichomes and that GaMYB2 may be a key regulator of cotton fiber development.
Reproductive Health in Afghanistan: Results of a Knowledge, Attitudes and Practices Survey among Afghan Women in Kabul
Authors: Van Egmond Kathia , Bosmans Marleen , Naeem Ahmad Jan , Claeys Patricia , Verstraelen Hans , Temmerman Marleen 
Published: September 2004

A reproductive‐health knowledge, attitudes and practices (KAP) survey was carried out among 468 Afghan women of reproductive age. A convenience sample of women was selected from attendees in the outpatient departments of four health facilities in Kabul. Seventy‐nine per cent of respondents had attended at least one antenatal consultation during their last pregnancy. Two‐thirds (67 per cent) delivered their first child between 13 and 19 years. The Caesarean‐section rate was low (1.6 per cent). Two‐thirds (67 per cent) of deliveries occurred in the home. The contraceptive prevalence rate was 23 per cent (16 per cent modern and 7 per cent natural methods). Twenty‐four per cent had knowledge of any STIs, although most of these women did not know correctly how to prevent them. Most of the women (93 per cent) needed authorization from their husband or a male relative before seeking professional health‐care.In multivariate analysis, women's schooling was significantly associated with antenatal‐care attendance (AOR 4.78), institutional delivery (AOR 2.29), skilled attendance at birth (AOR 2.07) and use of family planning (AOR 4.59).Reproductive‐health indicators were noted to be poor even among these women living in Kabul, a group often considered to be the most privileged. To meet the reproductive‐health needs of Afghan women, the socio‐cultural aspects of their situation — especially their decision‐making abilities — will need to be addressed.A long‐standing commitment from agencies and donors is required, in which the education of women should be placed as a cornerstone of the reconstruction process of Afghanistan.
Effect of obturation technique on sealer cement thickness and dentinal tubule penetration
Authors: Weis M. V. , Parashos P. , Messer H. H. 
Published: September 2004

AbstractAim  To compare the average sealer cement film thickness and the extent and pattern of sealer penetration into dentinal tubules in association with four obturation techniques in curved root canals.Methodology  Mesial canals of 44 extracted mandibular molars were randomly divided among the SimpliFill, continuous wave, Thermafil and 0.04 matched taper (master cones) lateral compaction obturation groups (22 canals per group). AH26 sealer cement was coloured blue‐black using Sudan Black B dye. Roots were sectioned 1, 3 and 5 mm from the working length. Specimens were photographed under 25× magnification, mounted as 35 mm slides and projected. Average sealer cement thickness (measured at 10 points around the canal wall), depth of dentinal tubule penetration and frequency of voids were determined at the 1, 3 and 5 mm levels. Data were analysed statistically for effect of obturation technique and level of section on sealer thickness and on the depth and distribution of tubule penetration.Results  Thermafil demonstrated superior GP adaptation at all levels with a mean overall sealer cement thickness of 2.2 μm, followed by lateral compaction (11.1 μm), continuous wave (12.2 μm) and SimpliFill (47.6 μm). SimpliFill also demonstrated the highest frequency of voids (P < 0.05). Sealer cement penetrated dentinal tubules as far as the outer one‐third of dentine, with greater penetration observed buccally or lingually (P < 0.001). Penetration was not significantly affected by obturation technique, but on average was deeper and more frequent at the 3 and 5 mm levels than at the 1 mm level (P < 0.001).Conclusions  Sealer thickness was strongly dependent on obturation technique. Assuming that minimal sealer thickness and fewer voids are good measures of long‐term sealing ability, Thermafil resulted in the best outcome. Consistent, extensive sealer penetration into dentinal tubules was seen and was unrelated to the obturation technique.
The effectiveness of syringe irrigation and ultrasonics to remove debris from simulated irregularities within prepared root canal walls
Authors: Lee S.‐J. , Wu M.‐K. , Wesselink P. R. 
Published: September 2004

AbstractAim  To compare the ability of syringe irrigation and ultrasonic irrigation to remove artificially placed dentine debris from simulated canal irregularities within prepared root canals.Methodology  After canal enlargement, twelve canines were split longitudinally into two halves. On the wall of one half of each root canal a standard groove of 4 mm in length, 0.2 mm in width and 0.5 mm in depth was cut, 2–6 mm from the apex, to simulate uninstrumented canal extensions. On the wall of the other half, three standard saucer‐shaped depressions of 0.3 mm in diameter and 0.5 mm in depth were cut at 2, 4 and 6 mm from the apex to simulate uninstrumented canal irregularities. Each groove and depression were filled with dentine debris mixed with 2% NaOCl to simulate a situation when dentine debris accumulates in uninstrumented canal extensions and irregularities during canal preparation. Each tooth was re‐assembled by reconnecting the two halves, using wire and an impression putty material. Two per cent NaOCl was then delivered into each canal either using syringe irrigation (n = 8) or using ultrasonic irrigation (n = 8). Before and after irrigation, images of the two halves of the canal wall were taken, using a microscope and a digital camera, after which they were scanned into a PC as TIFF images. The amount of remaining dentine debris in the grooves and depressions was evaluated by using a scoring system between 0–3: the higher the score, the more the debris. The data were analysed by means of the Mann–Whitney U‐test.Results  Both forms of irrigation reduced the debris score significantly. The debris score was statistically significantly lower after ultrasonic irrigation than after syringe irrigation (P = 0.002 for grooves, P = 0.047 for depressions).Conclusion  Ultrasonic irrigation ex vivo is more effective than syringe irrigation in removing artificially created dentine debris placed in simulated uninstrumented extensions and irregularities in straight, wide root canals.
Root canal obturation by ultrasonic condensation of gutta‐percha. Part II: an in vitro investigation of the quality of obturation
Authors: Bailey G. C. , Ng Y. ‐L. , Cunnington S. A. , Barber P. , Gulabivala K. , Setchell D. J. 
Published: September 2004

AbstractAim  To compare the quality of root canal obturation using ultrasonic or cold condensation of gutta‐percha and to determine the effect of power setting and activation time on the quality of obturation using the former technique.Methodology  An extracted human maxillary canine was used in an in vitro split tooth model to allow repeated obturation of the same root canal system using an ultrasonic device to thermocompact gutta‐percha without sealer. After each obturation, the root filling was removed from the tooth to allow evaluation of its quality and for the tooth to be re‐obturated. The influence of combinations (n = 10 per combination) of power setting (1, 3, 5) and activation times (4, 10, 15 s) was tested on the quality of root filling, assessed by measuring the voids within the body of the root filling as well as at the surface. Image analysis was used to quantify the voids within the body of the root filling. Cold lateral condensation of gutta‐percha served as a control.Results  Both surface and cross‐sectional analyses revealed that different power setting and activation time combinations produced significantly fewer voids than cold lateral condensation (P < 0.05) at the apical, mid‐root and coronal levels.Conclusions  Taking surface and cross‐sectional analysis together only power setting 5 and activation times of 10 and 15 s consistently produced ultrasonically thermocompacted root canal fillings with fewer voids than cold lateral condensation without sealer.
Biocompatibility of two commercial forms of mineral trioxide aggregate
Authors: Camilleri J. , Montesin F. E. , Papaioannou S. , McDonald F. , Pitt Ford T. R. 
Published: September 2004

AbstractAim  To examine the biocompatibility of two commercial forms of mineral trioxide aggregate (MTA), by evaluating the morphology of an established cell line.Methodology  The two cements were cast on glass cover slips and cured for 1 or 28 days. Saos‐2 osteosarcoma cells were trypsinized and seeded at a density of 1 × 105 cells and were then placed in medium over the material‐coated coverslips for 1, 5 and 7 days. After these time intervals the media were discarded and the cells fixed. Cell morphological investigation was performed by scanning electron microscopy at various magnifications ranging from × 250 to× 500. The biocompatibility of cement constituents, alusilicate flux and bismuth oxide was also investigated.Results  All cement samples cured for 1 day showed a confluent cell monolayer after 5 and 7 days. The response to both materials was similar. Materials cured for 28 days showed incomplete cell confluence after 1 and 5 days. Alusilicate flux and bismuth oxide did not demonstrate biocompatibility.Conclusions  The 1‐day cured samples of two commercial forms of MTA showed good biocompatibility. However, the 28‐day cured samples were less biocompatible after 1 and 5 days.
Central adenoid cystic carcinoma of the mandible manifesting as an endodontic lesion
Authors: Chen Y. K. , Chen C. H. , Lin C. C. , Hsue S. S. , Lin Y. R. , Lin L. M. 
Published: September 2004

AbstractAim  To present a case of adenoid cystic carcinoma (ACC) in the mandible, and manifesting as a periapical lesion.Summary  A 56‐year‐old male suffered from pain around the right mandibular first molar for approximately 1 week. Oral examination revealed that the involved tooth was restored by a full coverage crown with no obvious abnormalities. A periapical radiograph revealed two ill‐defined radiolucencies associated with the tooth, one over the mesial and another over the distal roots of the tooth; incomplete root filling and furcation involvement also being noted. The affected tooth was extracted based on the clinical impression of apical periodontitis. The surrounding tissue of the root apex was curetted and sent for histopathological examination, which revealed ACC.Key learning points

Adenoid cystic carcinoma affecting the mandible may mimic a periapical lesion. Proper diagnosis of such a lesion is dependent on thorough clinical, radiographic and microscopic examinations.
Such a case highlights the benefits of biopsy and histological examination of collected tissues.
Diagnosis of lesions in the mandible should include salivary gland tumours.
Susceptibility to localized corrosion of stainless steel and NiTi endodontic instruments in irrigating solutions
Authors: Darabara M. , Bourithis L. , Zinelis S. , Papadimitriou G. D. 
Published: September 2004

AbstractAim  To evaluate the pitting and crevice corrosion characteristics of stainless steel (SS) and NiTi endodontic files in R‐EDTA and NaOCl irrigating solutions.Methodology  The corrosion behaviour of two H‐files produced from different SS alloys (Mani, AISI 303 SS, Dentsply Maillefer, AISI 304 SS) and one file produced from NiTi alloy (Maillefer) was determined in R‐EDTA and NaOCl irrigating solutions by the cyclic potentiodynamic polarization method. The cutting flutes of 12 files of each material were embedded in an epoxy resin, polished, exposed to the irrigating solutions and used as an electrode. An Ag/AgCl electrode was used as a reference, a platinum plate was used as a counter electrode and polarization curves were obtained for all files in R‐EDTA and NaOCl irrigating solutions in 37 °C with a potential scan rate of 5 mV min−1. Corrosion potential (Ecorr), Corrosion current density (Icorr) and Pitting potential (Epit) were calculated from each curve. The results were statistically analysed with two‐way anova and Student‐Newman‐Keuls (SNK) multiple comparison test with materials and irrigating solutions serving as discriminating variables (a = 0.05).Results  Cyclic polarization curves presented negative hysteresis implying that pitting or crevice corrosion are not likely to occur for all the materials examined in both irrigating solutions. In NaOCl all materials showed significantly higher Ecorr (P = 0.011) as well as lower Icorr compared with R‐EDTA reagent. Moreover, all materials demonstrated equal Epit in NaOCl, which was to be found significantly lower (P = 0.009) than the value of Epit in R‐EDTA.Conclusions  None of the tested materials is susceptible to pitting or crevice corrosion in R‐EDTA and NaOCl solutions and from this standpoint are appropriate for the production of endodontic files.
Independent genetic mechanisms mediate turgor generation and penetration peg formation during plant infection in the rice blast fungus
Authors: Park Gyungsoon , Bruno Kenneth S. , Staiger Christopher J. , Talbot Nicholas J. , Xu Jin‐Rong 
Published: September 2004

SummaryThe first barrier to infection encountered by foliar pathogens is the host cuticle. To traverse this obstacle, many fungi produce specialized infection cells called appressoria. MST12 is essential for appressorium‐mediated penetration and infectious growth by the rice pathogen Magnaporthe grisea. In this study, we have characterized in detail the penetration defects of an mst12 deletion mutant. Appressoria formed by the mst12 mutant developed normal turgor pressure and ultrastructure but failed to form penetration pegs either on cellophane membranes or on plant epidermal cells. Deletion and site‐directed mutagenesis analyses indicated that both the homeodomain and zinc finger domains, but not the middle region, of MST12 are essential for appressorial penetration and plant infection. The mst12 mutant appeared to be defective in microtubule reorganization associated with penetration peg formation. In mature appressoria, the mutant lacked vertical microtubules observed in the wild type. The mst12 mutant also failed to elicit localized host defence responses, including papilla formation and autofluorescence. Our data indicate that generation of appressorium turgor pressure and formation of the penetration peg are two independent processes. MST12 may play important roles in regulating penetration peg formation and directing the physical forces exerted by the appressorium turgor in mature appressoria.
Characterization of IDI‐4, a bZIP transcription factor inducing autophagy and cell death in the fungus Podospora anserina
Authors: Dementhon Karine , Saupe Sven J. , Clavé Corinne 
Published: September 2004

SummaryIn filamentous fungi a cell death reaction occurs when hyphae of unlike genotype fuse. This phenomenon is referred to as heterokaryon incompatibility. In Podospora anserina, this cell death reaction was found to be associated with the transcriptional induction of a set of genes termed idi genes (for induced during incompatibility) and activation of autophagy. Herein, we describe the characterization of idi‐4, a novel idi gene encoding a bZIP transcription factor. Expression of idi‐4 is induced during cell death by incompatibility and in various stress conditions. Inactivation of idi‐4 by gene replacement does not suppress incompatibility but we show that overexpression of idi‐4 triggers cell death. Strains which undergo idi‐4‐induced cell death display cytological hallmarks of cell death by incompatibility notably induction of autophagy. We also report that increased expression of idi‐4 leads to transcriptional induction of other idi genes such as idi‐7, the orthologue of the yeast ATG8 autophagy gene. Together these results establish IDI‐4 as one of the transcription factor regulating autophagy and cell fate in Podospora.
Endoplasmic reticulum stress leads to the selective transcriptional downregulation of the glucoamylase gene in Aspergillus niger
Authors: Al‐Sheikh Hashem , Watson Adrian J. , Lacey Georgina A. , Punt Peter J. , MacKenzie Donald A. , Jeenes David J. , Pakula Tiina , Penttilä Merja , Alcocer Marcos J. C. , Archer David B. 
Published: September 2004

SummaryWe describe a new endoplasmic reticulum (ER)‐associated stress response in the filamentous fungus Aspergillus niger. The inhibition of protein folding within the ER leads to cellular responses known collectively as the unfolded protein response (UPR) and we show that the selective transcriptional downregulation of the gene encoding glucoamylase, a major secreted protein, but not two non‐secreted proteins, is an additional consequence of ER stress. The transcriptional downregulation effect is shown by nuclear run‐on studies to be at the level of transcription, rather than mRNA stability, and is found to be mediated through the promoter of glaA in a region more than 1 kb upstream of the translational start. The inhibition of protein folding in the ER can be induced in a variety of ways. We examined the effects of dithiothreitol (DTT), a reducing agent that causes the formation of unfolded proteins. Although a general downregulation of transcription was seen with DTT treatment, we show that selective downregulation was observed with the glaA gene compared with genes encoding the non‐secreted proteins γ‐actin and glyceraldehyde 3′‐phosphate dehydrogenase. The DTT‐treated fungal cells also showed evidence for the induction of the UPR because expression of bipA and pdiA, encoding an ER‐resident chaperone and foldase, respectively, are upregulated and splicing of hacA, the gene encoding the transcription factor responsible for induction of the UPR, occurs allowing the production of an active HacA protein. As a preliminary attempt to investigate if the transcriptional downregulation effect was mediated through HacA (i.e. part of the UPR), we examined ER stress induced through antisense technology to lower the level of PDI in the ER of A. niger. Although the transcription of glaA was attenuated in that strain of A. niger, UPR was not evident, suggesting that the transcriptional downregulation mechanism is controlled differently from the UPR.