bluuebunny/crossref_metadata_2025_split huggingface dataset:
White Leaf Sectors inyellow variegated2Are Formed by Viable Cells with Undifferentiated Plastids
Authors: Kato Yusuke , Miura Eiko , Matsushima Ryo , Sakamoto Wataru 
Published: April 2007

AbstractThe yellow variegated2 (var2) is one of the best-characterized Arabidopsis (Arabidopsis thaliana) mutants showing leaf variegation. Leaf variegation of var2 results from the loss of an ATP-dependent metalloprotease, FtsH2, which is a major component of the FtsH heterocomplex in thylakoid membranes. While the functional role of FtsH2 in protein quality control has been extensively studied, the physiological state of plastids in white tissues of the var2 is not well characterized. Here we show that the white tissue in var2 is neither the result of photobleaching nor enhanced senescence. Visualization of plastids by plastid-targeted green fluorescent protein revealed that plastids in the white sector are distinct and have undifferentiated characteristics. The plastids are also distinct in that they contain large nucleoids, a complex structure of plastid DNA and proteins, that are typically found in undifferentiated plastids. Comparative analyses of protein profiles from green and white tissues suggested that the difference was observed in the proteins related to photosynthesis but not due to proteins of other organelles. Thus, cells in the white tissue are viable and their defect is limited to plastid function. The plastid accumulates normal levels of chloroplast transcripts, whereas a substantial repression of nuclear-encoded photosynthetic genes was evident in the white sector. Based upon these results, we inferred that the white sectors in var2 are made by viable cells that have plastids arrested in thylakoid formation. A proposed model to form the variegated sector in var2 is provided.
Mutation ofE1-CONJUGATING ENZYME-RELATED1Decreases RELATED TO UBIQUITIN Conjugation and Alters Auxin Response and Development
Authors: Woodward Andrew W. , Ratzel Sarah E. , Woodward Erin E. , Shamoo Yousif , Bartel Bonnie 
Published: April 2007

AbstractThe ubiquitin-like protein RELATED TO UBIQUITIN (RUB) is conjugated to CULLIN (CUL) proteins to modulate the activity of Skp1-Cullin-F-box (SCF) ubiquitylation complexes. RUB conjugation to specific target proteins is necessary for the development of many organisms, including Arabidopsis (Arabidopsis thaliana). Here, we report the isolation and characterization of e1-conjugating enzyme-related1-1 (ecr1-1), an Arabidopsis mutant compromised in RUB conjugation. The ecr1-1 mutation causes a missense change located two amino acid residues from the catalytic site cysteine, which normally functions to form a thioester bond with activated RUB. A higher ratio of unmodified CUL1 relative to CUL1-RUB is present in ecr1-1 compared to wild type, suggesting that the mutation reduces ECR1 function. The ecr1-1 mutant is resistant to the auxin-like compound indole-3-propionic acid, produces fewer lateral roots than wild type, displays reduced adult height, and stabilizes a reporter fusion protein that is degraded in response to auxin, suggesting reduced auxin signaling in the mutant. In addition, ecr1-1 hypocotyls fail to elongate normally when seedlings are grown in darkness, a phenotype shared with certain other RUB conjugation mutants that is not general to auxin-response mutants. The suite of ecr1-1 molecular and morphological phenotypes reflects roles for RUB conjugation in many aspects of plant growth and development. Certain ecr1-1 elongation defects are restored by treatment with the ethylene-response inhibitor silver nitrate, suggesting that the short ecr1-1 root and hypocotyl result from aberrant ethylene accumulation. Further, silver nitrate supplementation in combination with various auxins and auxin-like compounds reveals that members of this growth regulator family may differentially rely on ethylene signaling to inhibit root growth.
MONODEHYROASCORBATE REDUCTASE4 Is Required for Seed Storage Oil Hydrolysis and Postgerminative Growth in Arabidopsis
Authors: Eastmond Peter J. 
Published: April 2007

Abstract
Hydrogen peroxide is a major by-product of peroxisomal metabolism and has the potential to cause critical oxidative damage. In all eukaryotes, catalase is thought to be instrumental in removing this H2O2. However, plants also contain a peroxisomal membrane–associated ascorbate-dependent electron transfer system, using ascorbate peroxidase and monodehydroascorbate reductase (MDAR). Here, I report that the conditional seedling-lethal sugar-dependent2 mutant of Arabidopsis thaliana is deficient in the peroxisomal membrane isoform of MDAR (MDAR4). Following germination, Arabidopsis seeds rely on storage oil breakdown to supply carbon skeletons and energy for early seedling growth, and massive amounts of H2O2 are generated within the peroxisome as a by-product of fatty acid β-oxidation. My data suggest that the membrane-bound MDAR4 component of the ascorbate-dependent electron transfer system is necessary to detoxify H2O2, which escapes the peroxisome. This function appears to be critical to protect oil bodies that are in close proximity to peroxisomes from incurring oxidative damage, which otherwise inactivates the triacylglycerol lipase SUGAR-DEPENDENT1 and cuts off the supply of carbon for seedling establishment.
TheArabidopsisD-Type Cyclin CYCD4 Controls Cell Division in the Stomatal Lineage of the Hypocotyl Epidermis
Authors: Kono Atsushi , Umeda-Hara Chikage , Adachi Sumiko , Nagata Noriko , Konomi Mami , Nakagawa Tsuyoshi , Uchimiya Hirofumi , Umeda Masaaki 
Published: April 2007

AbstractCyclin D (CYCD) plays an important role in cell cycle progression and reentry in response to external signals. Here, we demonstrate that Arabidopsis thaliana CYCD4 is associated with specific cell divisions in the hypocotyl. We observed that cycd4 T-DNA insertion mutants had a reduced number of nonprotruding cells and stomata in the hypocotyl epidermis. Conversely, CYCD4 overexpression enhanced cell division in nonprotruding cell files in the upper region of the hypocotyls, where stomata are usually formed in wild-type plants. The overproliferative cells were of stomatal lineage, which is marked by the expression of the TOO MANY MOUTHS gene, but unlike the meristemoids, most of them were not triangular. Although the phytohormone gibberellin promoted stomatal differentiation in the hypocotyl, inhibition of gibberellin biosynthesis did not prevent CYCD4 from inducing cell division. These results suggested that CYCD4 has a specialized function in the proliferation of stomatal lineage progenitors rather than in stomatal differentiation. We propose that CYCD4 controls cell division in the initial step of stomata formation in the hypocotyl.
The Transcription Factor WIN1/SHN1 Regulates Cutin Biosynthesis in Arabidopsis thaliana
Authors: Kannangara Rubini , Branigan Caroline , Liu Yan , Penfield Teresa , Rao Vijaya , Mouille Grégory , Höfte Herman , Pauly Markus , Riechmann José Luis , Broun Pierre 
Published: April 2007

Abstract
The composition and permeability of the cuticle has a large influence on its ability to protect the plant against various forms of biotic and abiotic stress. WAX INDUCER1 (WIN1) and related transcription factors have recently been shown to trigger wax production, enhance drought tolerance, and modulate cuticular permeability when overexpressed in Arabidopsis thaliana. We found that WIN1 influences the composition of cutin, a polyester that forms the backbone of the cuticle. WIN1 overexpression induces compositional changes and an overall increase in cutin production in vegetative and reproductive organs, while its downregulation has the opposite effect. Changes in cutin composition are preceded by the rapid and coordinated induction of several genes known or likely to be involved in cutin biosynthesis. This transcriptional response is followed after a delay by the induction of genes associated with wax biosynthesis, suggesting that the regulation of cutin and wax production by WIN1 is a two-step process. We demonstrate that at least one of the cutin pathway genes, which encodes long-chain acyl-CoA synthetase LACS2, is likely to be directly targeted by WIN1. Overall, our results suggest that WIN1 modulates cuticle permeability in Arabidopsis by regulating genes encoding cutin pathway enzymes.
An ERF Transcription Factor in Medicago truncatula That Is Essential for Nod Factor Signal Transduction
Authors: Middleton Patrick H. , Jakab Júlia , Penmetsa R. Varma , Starker Colby G. , Doll Jake , Kaló Péter , Prabhu Radhika , Marsh John F. , Mitra Raka M. , Kereszt Attila , Dudas Brigitta , VandenBosch Kathryn , Long Sharon R. , Cook Doug R. , Kiss Gyorgy B. , Oldroyd Giles E.D. 
Published: April 2007

Abstract
Rhizobial bacteria activate the formation of nodules on the appropriate host legume plant, and this requires the bacterial signaling molecule Nod factor. Perception of Nod factor in the plant leads to the activation of a number of rhizobial-induced genes. Putative transcriptional regulators in the GRAS family are known to function in Nod factor signaling, but these proteins have not been shown to be capable of direct DNA binding. Here, we identify an ERF transcription factor, ERF Required for Nodulation (ERN), which contains a highly conserved AP2 DNA binding domain, that is necessary for nodulation. Mutations in this gene block the initiation and development of rhizobial invasion structures, termed infection threads, and thus block nodule invasion by the bacteria. We show that ERN is necessary for Nod factor–induced gene expression and for spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase, DMI3, which is a component of the Nod factor signaling pathway. We propose that ERN is a component of the Nod factor signal transduction pathway and functions downstream of DMI3 to activate nodulation gene expression.
PIL5, a Phytochrome-Interacting bHLH Protein, Regulates Gibberellin Responsiveness by Binding Directly to theGAIandRGAPromoters inArabidopsisSeeds
Authors: Oh Eunkyoo , Yamaguchi Shinjiro , Hu Jianhong , Yusuke Jikumaru , Jung Byunghyuck , Paik Inyup , Lee Hee-Seung , Sun Tai-ping , Kamiya Yuji , Choi Giltsu 
Published: April 2007

AbstractPrevious work showed that PHYTOCHROME-INTERACTING FACTOR3-LIKE5 (PIL5), a light-labile basic helix-loop-helix protein, inhibits seed germination by repressing GIBBERELLIN 3β-HYDROXYLASE1 (GA3ox1) and GA3ox2 and activating a gibberellic acid (GA) catabolic gene (GA2ox2). However, we show persistent light-dependent and PIL5-inhibited germination behavior in the absence of both de novo GA biosynthesis and deactivation by GA2ox2, suggesting that PIL5 regulates not only GA metabolism but also GA responsiveness. PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness. The hypersensitivity of gai-t6 rga-28 to red light and the suppression of germination defects of a rga-28 PIL5 overexpression line show the significant role of this transcriptional regulation in seed germination. PIL5 also increases abscisic acid (ABA) levels by activating ABA biosynthetic genes and repressing an ABA catabolic gene. PIL5 binds directly to GAI and RGA promoters but not to GA and ABA metabolic gene promoters. Together, our results show that light signals perceived by phytochromes cause a reduction in the PIL5 protein level, which in turn regulates the transcription of two DELLA genes directly and that of GA and ABA metabolic genes indirectly.
Structural context for protein N‐glycosylation in bacteria: The structure of PEB3, an adhesin from Campylobacter jejuni
Authors: Rangarajan Erumbi S. , Bhatia Smita , Watson David C. , Munger Christine , Cygler Miroslaw , Matte Allan , Young N. Martin 
Published: April 2007

AbstractCampylobacter jejuni is unusual among bacteria in possessing a eukaryotic‐like system for N‐linked protein glycosylation at Asn residues in sequons of the type Asp/Glu‐Xaa‐Asn‐Xaa‐Ser/Thr. However, little is known about the structural context of the glycosylated sequons, limiting the design of novel recombinant glycoproteins. To obtain more information on sequon structure, we have determined the crystal structure of the PEB3 (Cj0289c) dimer. PEB3 has the class II periplasmic‐binding protein fold, with each monomer having two domains with a ligand‐binding site containing citrate located between them, and overall resembles molybdate‐ and sulfate‐binding proteins. The sequon around Asn90 is located within a surface‐exposed loop joining two structural elements. The three key residues are well exposed on the surface; hence, they may be accessible to the PglB oligosaccharyltransferase in the folded state.
Some ethical issues regarding xenotransfusion
Authors: Roux Françoise A. , Saï Pierre , Deschamps Jack‐Yves 
Published: April 2007

Abstract:  Background:  The use of porcine red blood cells has recently been proposed as a possible solution to the shortage of blood for human transfusion.Objectives:  The purpose of this paper is to compare some ethical issues regarding xenotransfusion (XTF) with those relating to xenotransplantation (XT) of organs, tissues and cells.Materials and methods:  Various ethical concerns and viewpoints relating to XTF are discussed.Results:  The main ethical obstacles to XT do not apply to XTF. It is much more ethically acceptable to raise pigs for regular blood collection as it doesn’t damage the health of the animal. Porcine endogenous retrovirus infection, the major concern associated with XT, does not apply to XTF, since red blood cells have no DNA and have a very short lifespan. Clinical trials will be possible in humans once XTF has been demonstrated to be effective and harmless in non‐human primates. Transgenesis is acceptable for pig blood donors because only a limited number of genes are involved, and these animals will never enter into the livestock gene pool or the food chain.Conclusion:  Because the need for blood is less pressing than that for organs, tissues or cells, the use of animal blood for human transfusion is not an absolute necessity. However, it represents a real opportunity. The ability to gain access to an unlimited quantity of blood is a reasonable justification for XTF. Because its technical and ethical hurdles are less stringent, XTF could be the first large‐scale clinical application of XT.
Two species of Dasya (Ceramiales, Rhodophyta) from Bonin Islands, southern Japan, with the description of Dasya boninensis sp. nov.
Authors: Masuda Michio , Kurihara Akira , Kogame Kazuhiro 
Published: April 2007

SUMMARYTwo species of Dasya in the Dasyaceae (Ceramiales, Rhodophyta) are reported from Bonin Islands, southern Japan. Dasya murrayana Abbott et Millar, new to Japan, is characterized by the following set of features: the tufted habit (up to 30 erect axes developing from a basal disc), small‐sized (6–10 mm high and 350–500 μm in diameter in the middle region), thinly but completely corticated axes, rigid and incurved pseudolaterals forming corymbose heads at the apices of axes and branches, the absence of adventitious monosiphonous filaments, a large number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral and slender spermatangial branches (35–45 μm in diameter). Dasya boninensis Masuda, Kurihara et Kogame, sp. nov. is characterized by short but thick (10–30 mm high and 600–1000 μm in diameter at the middle portion), heavily corticated axes, indistinct pericentral cells except for the upper portion in transverse sections, soft, straight pseudolaterals and adventitious monosiphonous filaments densely covering the axis and branches, a small number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral, thick spermatangial branches (65–90 μm in diameter), and short‐necked cystocarps. A dichotomous key to the taxa found in Japanese waters is given.
Notes on the genus Nupela (Bacillariophyceae) including the description of a new species, Nupela scissura sp. nov. and an expanded description of Nupela paludigena
Authors: Siver Peter A. , Hamilton Paul B. , Morales Eduardo A. 
Published: April 2007

SUMMARYTwo species of the diatom genus Nupela are reported from freshwater lakes situated along the Atlantic Coastal Plain of North Carolina, USA. One of the species, N. scissura sp. nov., is described as new and the description of the other, Nupela paludigena (Scherer) Lange‐Bertalot, is expanded to include a full suite of ultrastructural characters. Nupela scissura is a heterovalvar taxon with one valve having a fully developed raphe identical in structure to those found on other Nupela species. The other valve lacks a true raphe, but presents one to several elongated slits in the apical portion of the sternum. The true identity of the slits, whether they represent a highly reduced raphe, a rudimentary raphe, or neither is unknown. In addition, both valves of a single N. scissura frustule differ in the structure of the axial and central areas. The structure of the areolae and details of the raphe clearly place this species in Nupela. Nupela paludigena (Scherer) Lange‐Bertalot was originally described in the genus Anomoeoneis from acidic and humic localities from the south‐eastern part of the Atlantic Coastal Plain and later transferred to Nupela. Although this species has rarely been reported since its description, our findings indicate that it is a common component of the floras in the Carolina bays of North Carolina. The characteristics currently used to circumscribe taxa within the genus Nupela are discussed in light of published work and our own observations.
ES02 SIGNIFICANCE OF LYMPH NODE MICROMETASTASES IN PAPILLARY THYROID CARCINOMA
Authors: Cranshaw I. M. , Jany T. , Arnalsteen L. , Pattou F. , Carnaille B. 
Published: April 2007

Purpose  Management of nodal disease in papillary thyroid cancer (PTC) varies. The significance of micrometastases and their relationship to locoregional recurrence has not been well described. We set out to compare patients with micrometastatic nodal disease to those with macrometastases and those with no metastases. Our service follows a policy of routine central/recurrent nerve dissection and ipsilateral jugulocarotid node sampling for cases of PTC.Methodology  One hundred and seventy patients who had surgery for PTC between January 1995 and December 2000 were included and split into three groups. Micrometastases (only micrometastatic disease), Macrometastases (any macrometastaic nodal involvement) and No metastases (absence of any nodal involvement). These three groups were compared for rates of locoregional disease recurrence and distant metastases.Results  Contingency analysis showed that the Macrometastases group had a significantly higher rate of locoregional recurrence compared with both No metastases(Odds ratio 7.67, p < 0.0001) and Micrometastases groups (Odds ratio 9.212, p 0.0154). There was no difference between the No metastases and micrometastases groups (p 1.000), the p value suggesting the two groups were likely to be equivalent. Analysis revealed that distant disease was significantly more common in the Macrometastases group when compared to the No metastases group, (Odds ratio 25.09, p 0.0032)Conclusions  Micrometastatic nodal disease associated with PTC does not lead to higher rates of locoregional recurrence or distant disease. These patients do not need completion neck dissection and have a low risk of locoregional recurrence.
GS26P ABDOMINAL WALL ENDOMETRIOMA FOLLOWING CAESAREAN SECTION
Authors: Whitfield R. J. , Worley P. J. , Hughes C. D. G. 
Published: April 2007

Purpose  Endometriosis is defined as the presence of aberrant endometrial tissue outside of the uterus that responds to stimulation by ovarian hormones. A large, circumscribed mass of such tissue is commonly termed an endometrioma. Abdominal wall endometriomas in association with caesarean section scars have been reported repeatedly in the obstetrics and gynaecology literature, but rarely in general surgical journals.Methodology  In this paper, six patients are reviewed who presented between 2001 and 2006 with painful, tender nodules in and around caesarean section scars. Of these, four reported exacerbation of symptoms during, or just prior to menstruation. One patient had experienced 12 years of symptoms, previously attributed to intra‐abdominal adhesions.Results  All patients had their scar nodules excised. Five procedures were performed electively. One patient underwent emergency exploration of her caesarean scar for possible incarcerated incisional hernia. Ectopic endometrial tissue was seen in the histological specimens of all patients. Four patients reported resolution of their symptoms following surgery. One patient had ongoing symptoms post‐operatively, with an additional mass lesion seen on ultrasound consistent with a second endometrioma. One patient did not attend follow‐up.Conclusion  General surgeons are commonly required to assess and manage abdominal wall masses, and should have an awareness of endometrioma in the differential diagnosis when such a lesion is seen in association with a caesarean section scar. Wide excision is usually very effective at alleviating symptoms of abdominal wall endometrioma.
HP24 MICRORNA EXPRESSION PROFILES IN BARRETT’S OESOPHAGUS
Authors: Watson D. I. , Wijnhoven B. P. L. , Michael M. Z. , Mayne G. C. , Hussey D. J. 
Published: April 2007

Purpose  The genetic changes that drive the metaplastic change from squamous oesophagus (NO) towards Barrett’s oesophagus (BO) and cancer are unclear. microRNAs (miRNAs) are short, non‐coding RNAs that regulate gene expression and contribute to cellular differentiation and identity. We sought to determine the role of miRNAs in BO.Methodology  Biopsies of NO, BO and cardia were taken from 7 patients and RNA was extracted. miRNA expression profiles of 300 miRNAs were determined by microarray. Guided by the array results, real‐time Reverse Transcriptase‐Polymerase Chain Reaction (RT‐PCR) for 8 selected miRNAs enabled their expression to be studied in tissues from another 15 patients.Results  Array data revealed that 39 miRNAs were significantly differentially expressed between NO, BO and cardia. A tissue‐specific expression profile was confirmed by RT‐PCR, with miR‐21, 143, 145, 194 and 215 significantly up regulated in BO and cardia (columnar) vs. NO (squamous). A trend towards increased miR‐21 expression from NO to BO and adenocarcinoma was observed (p = 0.1). Interestingly, high expression of miR‐143, 194 and 215 was seen in BO vs. NO (p < 0.0001), but with subsequent downregulation in cancers (p = 0.1). In contrast, miR‐203 and 205 were highly expressed in NO and low in BO and cardia. A database search revealed that these miRNAs potentially target (proto‐)oncogenes and tumour suppressor genes.Conclusions  Differences in miRNA expression are present between NO, BO, cardia and cancer. Deregulation of certain miRNAs, and their predicted effect on the expression of target genes, might contribute to the metaplastic and neoplastic process in the oesophagus and could serve as novel biomarkers to classify diseased tissues.