bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteomic analysis of leaf proteins during dehydration of the resurrection plant Xerophyta viscosa
Authors: INGLE ROBERT A. , SCHMIDT ULRIKE G. , FARRANT JILL M. , THOMSON JENNIFER A. , MUNDREE SAGADEVAN G. 
Published: January 2007

ABSTRACTThe desiccation‐tolerant phenotype of angiosperm resurrection plants is thought to rely on the induction of protective mechanisms that maintain cellular integrity during water loss. Two‐dimensional (2D) sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) analysis of the Xerophyta viscosa Baker proteome was carried out during dehydration to identify proteins that may play a role in such mechanisms. Quantitative analysis revealed a greater number of changes in protein expression levels at 35% than at 65% relative water content (RWC) compared to fully hydrated plants, and 17 dehydration‐responsive proteins were identified by tandem mass spectrometry (MS). Proteins showing increased abundance during drying included an RNA‐binding protein, chloroplast FtsH protease, glycolytic enzymes and antioxidants. A number of photosynthetic proteins declined sharply in abundance in X. viscosa at RWC below 65%, including four components of photosystem II (PSII), and Western blot analysis confirmed that two of these (psbP and Lhcb2) were not detectable at 30% RWC. These data confirm that poikilochlorophylly in X. viscosa involves the breakdown of photosynthetic proteins during dismantling of the thylakoid membranes. In contrast, levels of these photosynthetic proteins were largely maintained during dehydration in the homoiochlorophyllous species Craterostigma plantagineum Hochst, which does not dismantle thylakoid membranes on drying.
The Arabidopsis thaliana sulfiredoxin is a plastidic cysteine‐sulfinic acid reductase involved in the photooxidative stress response
Authors: Rey Pascal , Bécuwe Noëlle , Barrault Marie‐Bénédicte , Rumeau Dominique , Havaux Michel , Biteau Benoît , Toledano Michel B. 
Published: January 2007

SummaryThe 2‐cysteine peroxiredoxins (2‐Cys‐Prxs) are antioxidants that reduce peroxides through a thiol‐based mechanism. During catalysis, these ubiquitous enzymes are occasionally inactivated by the substrate‐dependent oxidation of the catalytic cysteine to the sulfinic acid (‐SO2H) form, and are reactivated by reduction by sulfiredoxin (Srx), an enzyme recently identified in yeast and in mammal cells. In plants, 2‐Cys‐Prxs constitute the most abundant Prxs and are located in chloroplasts. Here we have characterized the unique Srx gene in Arabidopsis thaliana (AtSrx) from a functional point of view, and analyzed the phenotype of two AtSrx knockout (AtSrx–) mutant lines. AtSrx is a chloroplastic enzyme displaying sulfinic acid reductase activity, as shown by the ability of the recombinant AtSrx to reduce the overoxidized 2‐Cys‐Prx form in vitro, and by the accumulation of the overoxidized Prx in mutant lines lacking Srx in vivo. Furthermore, AtSrx mutants exhibit an increased tolerance to photooxidative stress generated by high light combined with low temperature. These data establish that, as in yeast and in mammals, plant 2‐Cys‐Prxs are subject to substrate‐mediated inactivation reversed by Srx, and suggest that the 2‐Cys‐Prx redox status and sulfiredoxin are parts of a signaling mechanism participating in plant responses to oxidative stress.
HY5 is a point of convergence between cryptochrome and cytokinin signalling pathways in Arabidopsis thaliana
Authors: Vandenbussche Filip , Habricot Yvette , Condiff Amanda S. , Maldiney Régis , Straeten Dominique Van Der , Ahmad Margaret 
Published: January 2007

SummaryBlue‐light‐dependent photomorphogenesis in Arabidopsis is regulated principally by the cryptochrome flavin‐type photoreceptors, which control hypocotyl growth inhibition, cotyledon and leaf expansion, and the expression of light‐regulated genes. Interestingly the plant hormone cytokinin induces similar responses when added exogenously to germinating seedlings, suggesting a link between cryptochrome and cytokinin signalling pathways. In this work we explore the relationship between cryptochrome and cytokinin signalling pathways in the promotion of photomorphogenesis. The effect of exogenously added cytokinins on hypocotyl growth inhibition occurs in the dark, and is largely independent and additive to that of cryptochromes in blue light, via distinct signalling pathways. By contrast, cytokinin‐dependent stimulation of anthocyanin accumulation occurs only in light, and interacts with the signalling pathway downstream of cryptochrome 1 (CRY1) at the level of transcript accumulation of anthocyanin biosynthetic genes. Mutants in elongated hypocotyl 5 (hy5), a downstream intermediate in the CRY1 signalling pathway, show a reduced induction of anthocyanin accumulation in blue light by cytokinins, similar to that observed for cryptochrome (cry1) mutants. Furthermore cytokinins are shown to increase levels of HY5 protein accumulation, suggesting that cytokinins may function by reducing HY5 degradation by COP1 (constitutively photomorphogenic 1). As both cryptochrome and cytokinin signalling pathways increase HY5 protein levels, and as HY5 binds to the promoters of anthocyanin biosynthetic enzymes to stimulate gene expression, it is concluded that the regulation of HY5 protein stability represents a point of convergence between cryptochrome and cytokinin signalling pathways.
Dynamics of MONOPTEROS and PIN‐FORMED1 expression during leaf vein pattern formation in Arabidopsis thaliana
Authors: Wenzel Carol L. , Schuetz Mathias , Yu Qian , Mattsson Jim 
Published: January 2007

SummaryGenetic evidence links the Arabidopsis MONOPTEROS (MP) and PIN‐FORMED1 (PIN1) genes to the patterning of leaf veins. To elucidate their potential functions and interactions in this process, we have assessed the dynamics of MP and PIN1 expression during vascular patterning in Arabidopsis leaf primordia. Both genes undergo a dynamic process of gradual refinement of expression into files one to two cells wide before overt vascular differentiation. The subcellular distribution of PIN1 is also gradually refined from a non‐polar distribution in isodiametric cells to strongly polarized in elongated procambial cells and provides an indication of overall directions of auxin flow. We found evidence that MP expression can be activated by auxin exposure and that PIN1 as well as DR5::GUS expression is defective in mp mutant leaves. Taken together the results suggest a feedback regulatory loop that involves auxin, MP and PIN1 and provide novel experimental support for the canalization‐of‐auxin‐flow hypothesis.
The ubiquitin pathway is required for innate immunity in Arabidopsis
Authors: Goritschnig Sandra , Zhang Yuelin , Li Xin 
Published: January 2007

SummaryPlant defences require a multitude of tightly regulated resistance responses. In Arabidopsis, the unique gain‐of‐function mutant suppressor of npr1‐1 constitutive 1 (snc1) carries a point mutation in a Resistance (R)‐gene, resulting in constitutive activation of defence responses without interaction with pathogens. This has allowed us to identify various downstream signalling components essential in multiple defence pathways. One mutant that suppresses snc1‐mediated constitutive resistance is modifier of snc1 5 (mos5), which carries a 15‐bp deletion in UBA1, one of two ubiquitin‐activating enzyme genes in Arabidopsis. A mutation in UBA2 does not suppress snc1, suggesting that these two genes are not equally required in Arabidopsis disease resistance. On the other hand, a mos5 uba2 double mutant is lethal, implying partial redundancy of the two homologues. Apart from affecting snc1‐mediated resistance, mos5 also exhibits enhanced disease susceptibility to a virulent pathogen and is impaired in response to infection with avirulent bacteria carrying the protease elicitor AvrRpt2. The mos5 mutation in the C‐terminus of UBA1 might affect binding affinity of the downstream ubiquitin‐conjugating enzymes, thus perturbing ubiquitination of target proteins. Furthermore, SGT1b and RAR1, which are necessary for resistance conferred by the SNC1‐related R‐genes RPP4 and RPP5, are dispensable in snc1‐mediated resistance. Our data reveal the definite requirement for the ubiquitination pathway in the activation and downstream signalling of several R‐proteins.
ABA induction of miR159 controls transcript levels of two MYB factors during Arabidopsis seed germination
Authors: Reyes José L. , Chua Nam‐Hai 
Published: January 2007

SummaryUpon seed imbibition, abscisic acid (ABA) levels decrease to allow embryos to germinate and develop into seedlings. However, under abiotic stress conditions, ABA levels remain high, and growth and development are arrested. Several transcription factors, including abscisic acid‐insensitive (ABI)3 and ABI5, are known to control this developmental checkpoint. Here, we show that, in germinating Arabidopsis thaliana seeds, ABA induces the accumulation of microRNA 159 (miR159) in an ABI3‐dependent fashion, and miRNA159 mediates cleavage of MYB101 and MYB33 transcripts in vitro and in vivo. The two MYB transcription factors function as positive regulators of ABA responses, as null mutants of myb33 and myb101 show hyposensitivity to the hormone. Consistent with this, miR159 over‐expression suppresses MYB33 and MYB101 transcript levels and renders plants hyposensitive to ABA, whereas transgenic plants over‐expressing cleavage‐resistant forms of MYB33 and MYB101 are hypersensitive, as are plants over‐expressing the Turnip mosaic virus (TuMV) P1/HC‐Pro viral protein that is known to inhibit miRNA function. Our results suggest that ABA‐induced accumulation of miR159 is a homeostatic mechanism to direct MYB33 and MYB101 transcript degradation to desensitize hormone signaling during seedling stress responses.
Early events in the pathogenicity of Pseudomonas syringae on Nicotiana benthamiana
Authors: Hann Dagmar R. , Rathjen John P. 
Published: January 2007

SummaryConserved microbial molecules known as PAMPs (pathogen‐associated molecular patterns) elicit defence responses in plants through extracellular receptor proteins. One important PAMP is the flagellin protein derived from motile bacteria. We show here that the solanaceous species Nicotiana benthamiana perceives the flagellin proteins of both pathogenic and non‐host species of Pseudomonas syringae. The response to flagellin required a gene closely related to that encoding the Arabidopsisthaliana flagellin receptor that we designated NbFls2. In addition, silencing of NbFls2 led to increased growth of compatible, non‐host and non‐pathogenic strains of P. syringae. Thus, flagellin perception restricts growth of P. syringae strains on N. benthamiana. Pathogenic bacteria secrete effector proteins into the plant cell to enhance virulence. We tested the ability of several unrelated effectors to suppress PAMP‐mediated defences. The effector proteins AvrPto and AvrPtoB, but not AvrRps4, suppressed all responses tested including the hypersensitive response induced by non‐host flagellins and the oomycete elicitor INF1. Strikingly, transient expression of avrPto or avrPtoB stimulated the growth of non‐pathogenic Agrobacterium tumefaciensin planta, suggesting that multiplication of this species is also restricted by PAMP perception. Unexpectedly, AvrPtoB but not AvrPto required the defence‐associated genes Rar1, Sgt1 and Eds1 for suppression. This observation separates the respective mechanisms of the two effectors, and suggests that AvrPtoB may target the defence machinery directly for its suppressive effect.
The miRNA156/157 recognition element in the 3′ UTR of the Arabidopsis SBP box gene SPL3 prevents early flowering by translational inhibition in seedlings
Authors: Gandikota Madhuri , Birkenbihl Rainer P. , Höhmann Susanne , Cardon Guillermo H. , Saedler Heinz , Huijser Peter 
Published: January 2007

SummarymiRNAs are a class of versatile small RNAs that control gene expression post‐transcriptionally, governing many facets of plant cell functions. They interact with their target mRNA at a site of sequence complementarity and modulate their expression levels. Here, we provide evidence, based on transient assays and stable transgenic lines, that the 3′ UTR of the Arabidopsis SBP box gene SPL3 contains a functional miRNA‐responsive element (MRE) that is complementary to miR156 and miRNA157. Seedlings of transgenic lines constitutively over‐expressing an SPL3 transgene either carrying an unaltered or a disrupted MRE accumulate considerable levels of SPL3 transcripts. However, while the unaltered MRE UTR does not allow the expression of detectable levels of SPL3 protein, the altered MRE does. Translational inhibition thus provides an important mechanism for miRNA‐mediated post‐transcriptional repression of SPL3. As a consequence of precocious translation of the constitutively expressed SPL3 transgene, due to the absence of a functional MRE, plants exhibit very early flowering in addition to frequent morphological changes.
Relation between human decay‐accelerating factor (hDAF) expression in pig cells and inhibition of human serum anti‐pig cytotoxicity: value of highly expressed hDAF for xenotransplantation
Authors: Liu DaGe , Kobayashi Takaaki , Onishi Akira , Furusawa Tadashi , Iwamoto Masaki , Suzuki Shunichi , Miwa Yuko , Nagasaka Takaharu , Maruyama Shoichi , Kadomatsu Kenji , Uchida Kazuharu , Nakao Akimasa 
Published: January 2007

Abstract:  Background:  Although the successful production of α1,3‐galactosyltransferase‐knockout (GT‐KO) pigs has increased expectations of clinical xenotransplantation, additional modifications of genetically engineered pigs are still being explored, because even GT‐KO pigs are incapable of inhibiting the host's immunological response completely. One of the potential candidates is a complement‐regulatory protein, such as human decay‐accelerating factor (hDAF). However, there are few reports on how high the expression level of hDAF in pig cells would be required for suppression of complement activation. The purpose of this study was to examine the relationship between the level of hDAF expression and its inhibitory effect on human serum cytotoxicity.Methods:  An expression (pCAGGS) vector containing the hDAF gene was transfected into pig fibroblasts using an electroporation system (Gene Pulser II). Forty‐eight to fifty‐two hours after transfection, the cells were stained with FITC‐labeled anti‐hDAF antibody and then applied to the cell sorter. hDAF‐transfected cells with various expression levels were collected by gating on fluorescence intensity. The level of hDAF expression was determined relative to that in human control endothelial cells. Collected cells expressing ×1, ×5, ×10, ×15 and ×30 hDAF were incubated into 96‐well plates for 16 h, and the cells were subjected to 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay.Results:  hDAF expression levels in transfected cells at the time of MTT assay (16 h after sorting) were comparable to those immediately after sorting. hDAF expression in pig cells five times higher than in human endothelial cells was effective in inhibiting complement‐dependent cytotoxicity of most human sera. However, 15‐ to 30‐fold expression of hDAF was required for effective inhibition of human sera with the highest cytotoxic capacity.Conclusions:  A much higher level of hDAF expression in pig cells than previously considered necessary might be required to provide additional benefit in inhibiting antibody‐mediated rejection. Genetically engineered pigs that express very high levels of hDAF would be beneficial for xenotransplantation.
Isolation outcome and functional characteristics of young and adult pig pancreatic islets for transplantation studies
Authors: Bottino Rita , Balamurugan A. N. , Smetanka Cynthia , Bertera Suzanne , He Jing , Rood Pleunie P. M. , Cooper David K. C. , Trucco Massimo 
Published: January 2007

Abstract: Introduction:  Pig islets have been proposed as an alternative to human islets for clinical use, but their use is limited by rejection. The availability of genetically modified pigs devoid of α1,3‐galactosyltransferase might provide islets more suitable for xenotransplantation. To limit the costs involved in the logistics and health care of pigs for clinical xenotransplantation, we have studied whether younger, rather than older, pigs that are typically preferred can be used as islet donors.Methods:  We utilized pancreases from Yorkshire and White Landrace wild‐type pigs and α1,3‐galactosyltransferase gene‐knockout pigs of three main different age and size groups: (i) <6 months, (ii) 6 to 12 months, and (iii) >2 yr of age, inclusive of retired breeders. We compared isolation yield and in vitro and in vivo function of islet cells obtained from these groups.Results:  Islets from adult pigs (>2 yr) offered not only higher islet yields, but retained the ability to preserve intact morphology during the isolation process and culture, in association with high functional properties after transplantation. Following isolation, islet cells from young (<6 m) and young‐adult (6 to 12 m) pigs dissociated into small aggregates and single cells, and exhibited inferior functional properties than adult islets both in vitro and in vivo.Conclusions:  These data support the conclusion that, in view of the large number of islets needed to maintain normoglycemia after xenotransplantation, organ‐source pigs need to reach adult age (>2 yr) before being considered optimal islet donors, in spite of the higher costs involved.
Polyandry in coal tits Parus ater: fitness consequences of putting eggs into multiple genetic baskets
Authors: SCHMOLL T. , SCHURR F. M. , WINKEL W. , EPPLEN J. T. , LUBJUHN T. 
Published: January 2007

AbstractFemales of many species mate with multiple males within a single reproductive cycle. One hypothesis to explain polyandry postulates that females benefit from increasing within‐brood genetic diversity. Two mechanisms may render sire genetic diversity beneficial for females, genetic bet‐hedging vs. non‐bet‐hedging. We analysed whether females of the socially monogamous coal tit (Parus ater) benefit via either of these mechanisms when engaging in extra‐pair (i.e. polyandrous) mating. To obtain a measure of within‐brood genetic diversity as a function of paternal genetic contributions, we calculated a sire diversity index based on the established Shannon–Wiener Index. In 246 broods from two consecutive years, sire genetic diversity had no effect on either the mean or the variance in brood fitness measured as offspring recruitment within 4 years after birth. The hypothesis that benefits of increasing sire diversity contribute to selection for female extra‐pair mating behaviour in P. ater was therefore not supported.
Body shape vs. colour associated initial divergence in theTelmatherinaradiation in Lake Matano, Sulawesi, Indonesia
Authors: ROY D. , DOCKER M. F. , HAFFNER G. D. , HEATH D. D. 
Published: January 2007

AbstractHighly polymorphic colouration patterns are often associated with sexual selection in fish and can be the initial cause of divergence among closely related taxa. Here we use genetic, body colour and geometric morphometric data collected on 118 fish from Lake Matano, Sulawesi, Indonesia to test if colouration is the initial cause of divergence in the radiatingTelmatherinagenus. Results reveal that allTelmatherinapreviously described in this system can be categorized into three mitochondrial lineages and that colouration is only weakly associated with early divergence. Clade‐specific body shapes, however, likely adapted to microenvironments are key to the initial divergence in this system. Data also show that although colourations were not likely instrumental in seeding divergence in these fish, they appear to have developed in parallel within each clade. Our results are consistent with an emerging pattern repeated in many vertebrate radiations, whereby divergence by colouration or other display traits is preceded by specialization to environmental adaptive peaks.
Association of microsomal epoxide hydrolase gene polymorphism and pre‐eclampsia in Turkish women
Authors: Pinarbasi Ergun , Percin Ferda E. , Yilmaz Meral , Akgun Egemen , Cetin Meral , Cetin Ali 
Published: January 2007

AbstractAim:  To assess the association between human epoxide hydrolase exon 3 and 4 polymorphisms and pre‐eclampsia by carrying out a case‐control study in Turkish women.Methods:  DNA was extracted from peripheral blood leukocytes, and genotype distribution of exon 3 and exon 4 of epoxide hydrolase gene (EPHX) was carried out in 271 patients and 155 controls.Results:  There was no statistically significant difference in the distribution of genotypes between pre‐eclampsia without HELLP and pre‐eclampsia plus HELLP cases and controls for the exon 3 and 4 polymorphism of EPHX. However, we found a significant association between the predicted enzyme activity level and pre‐eclampsia (P = 0.018). The distribution of subjects with predicted high, intermediate and low microsomal epoxide hydrolase enzyme (EPHX) activity were 23.2, 38.8 and 38% in cases and 12, 47.3 and 40.7% in controls, respectively.Conclusion:  Although we could not find any association between genetic variability in exon 3 and 4 of EPHX and pre‐eclampsia, genetic variability in these two exons jointly modifies the predicted enzyme activity and may be a risk factor for pre‐eclampsia.
Tibolone therapy in breast cancer survivors: A retrospective study
Authors: Goutzioulis Michalis , Vavilis Dimitrios , Agorastos Theodoros , Konstantinidis Theodoros , Pantazis Konstantinos , Goutzioulis Antonios , Goulis Dimitrios G. , Makedos George , Bontis John N. 
Published: January 2007

AbstractAim:  To investigate a possible relationship between tibolone therapy and recurrence or mortality in breast cancer survivors.Methods:  In a retrospective study, data from files of 247 patients who had been treated for breast cancer were analyzed. Twenty women were treated with tibolone because of menopausal symptoms (Group 1: mean duration of tibolone use 37.1 months). One hundred and one women who did not take tibolone were selected as the control group (Group 2). All women were followed up in our Department on our standard protocol (mean follow up: 73.4 months in Group 1, 67.4 months in Group 2). Comparison of the survival curves was applied with the Wilcoxon (Gehan) statistic. Cox regression analysis was also applied in order to identify significant coefficients in the survival curve.Results:  Recurrence of breast cancer was observed in two (10%) Group 1 women versus 21 (21%) Group 2 women (P = NS). Two Group 1 women died (one from breast cancer recurrence) versus 15 Group 2 women (14 from breast cancer recurrence).Conclusions:  Despite of the inherent limitations of this small retrospective study, it seems that tibolone does not reveal an apparent negative impact on breast cancer outcome when given to breast cancer survivors.