bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of RTE1 in conformational changes promoting ETR1 ethylene receptor signaling in Arabidopsis
Authors: Resnick Josephine S. , Rivarola Maximo , Chang Caren 
Published: July 2008

SummaryEthylene is an important regulator of plant growth, development and responses to environmental stresses. Arabidopsis perceives ethylene through five homologous receptors that negatively regulate ethylene responses. RTE1, a novel gene conserved in plants, animals and some protists, was recently identified as a positive regulator of the ETR1 ethylene receptor. Here, we genetically analyze the dependence of ETR1 on RTE1 in order to obtain further insight into RTE1 function. The function of RTE1 was found to be independent and distinct from that of RAN1, which encodes a copper transporter required for ethylene receptor function. We tested the ability of an rte1 loss‐of‐function mutation to suppress 11 etr1 ethylene‐binding domain mis‐sense mutations, all of which result in dominant ethylene insensitivity due to constitutive signaling. This suppression test uncovered two classes of etr1 mutations –RTE1‐dependent and RTE1‐independent. The nature of these mutations suggests that the ethylene‐binding domain is a possible target of RTE1 action. Based on these findings, we propose that RTE1 promotes ETR1 signaling through a conformational effect on the ethylene‐binding domain.
GLK transcription factors regulate chloroplast development in a cell‐autonomous manner
Authors: Waters Mark T. , Moylan Elizabeth C. , Langdale Jane A. 
Published: July 2008

SummaryIn a number of land plants, Golden2‐like (GLK) genes encode a pair of partially redundant nuclear transcription factors that are required for the expression of nuclear photosynthetic genes and for chloroplast development. As chloroplast biogenesis depends on close co‐operation between the nuclear and plastid compartments, GLK gene function must be dependent on tight intracellular control. However, the extent to which GLK‐mediated chloroplast development depends on intercellular communication is not known. Here we used sector analysis to show that GLK proteins operate cell‐autonomously in leaf mesophyll cells. To establish whether GLK proteins are able to influence adjacent cell layers, we used tissue‐specific promoters to restrict GLK gene expression to the epidermis and to the phloem. GLK genes driven by the Arabidopsis epidermal FIDDLEHEAD (FDH) and MERISTEM LAYER1 (AtML1) promoters failed to rescue the pale‐green Atglk1 Atglk2 mutant phenotype, confirming the suggestion that GLK proteins can only influence chloroplast development intracellularly. An exception to this rule was seen in lines in which GLK genes were expressed in the phloem. However, we believe that the partial complementation of the mutant phenotype that was observed resulted from phloem unloading, as opposed to inherent properties of GLK proteins. We conclude that GLK proteins act in a cell‐autonomous manner to coordinate and maintain the photosynthetic apparatus within individual cells. Significantly, this suggests that GLK proteins provide a means to fine‐tune photosynthesis according to the differential requirements of cells within the leaf.
Stress generation in the tension wood of poplar is based on the lateral swelling power of the G‐layer
Authors: Goswami Luna , Dunlop John W.C. , Jungnikl Karin , Eder Michaela , Gierlinger Notburga , Coutand Catherine , Jeronimidis George , Fratzl Peter , Burgert Ingo 
Published: July 2008

SummaryThe mechanism of active stress generation in tension wood is still not fully understood. To characterize the functional interdependency between the G‐layer and the secondary cell wall, nanostructural characterization and mechanical tests were performed on native tension wood tissues of poplar (Populus nigra × Populus deltoids) and on tissues in which the G‐layer was removed by an enzymatic treatment. In addition to the well‐known axial orientation of the cellulose fibrils in the G‐layer, it was shown that the microfibril angle of the S2‐layer was very large (about 36°). The removal of the G‐layer resulted in an axial extension and a tangential contraction of the tissues. The tensile stress–strain curves of native tension wood slices showed a jagged appearance after yield that could not be seen in the enzyme‐treated samples. The behaviour of the native tissue was modelled by assuming that cells deform elastically up to a critical strain at which the G‐layer slips, causing a drop in stress. The results suggest that tensile stresses in poplar are generated in the living plant by a lateral swelling of the G‐layer which forces the surrounding secondary cell wall to contract in the axial direction.
Identification of a functionally essential amino acid for Arabidopsis cyclic nucleotide gated ion channels using the chimeric AtCNGC11/12 gene
Authors: Baxter Joyce , Moeder Wolfgang , Urquhart William , Shahinas Dea , Chin Kimberley , Christendat Dinesh , Kang Hong‐Gu , Angelova Magdalena , Kato Naohiro , Yoshioka Keiko 
Published: July 2008

SummaryWe used the chimeric Arabidopsis cyclic nucleotide‐gated ion channel AtCNGC11/12 to conduct a structure–function study of plant cyclic nucleotide‐gated ion channels (CNGCs). AtCNGC11/12 induces multiple pathogen resistance responses in the Arabidopsis mutant constitutive expresser of PR genes 22 (cpr22). A genetic screen for mutants that suppress cpr22‐conferred phenotypes identified an intragenic mutant, #73, which has a glutamate to lysine substitution (E519K) at the beginning of the eighth β‐sheet of the cyclic nucleotide‐binding domain in AtCNGC11/12. The #73 mutant is morphologically identical to wild‐type plants and has lost cpr22‐related phenotypes including spontaneous cell death and enhanced pathogen resistance. Heterologous expression analysis using a K+‐uptake‐deficient yeast mutant revealed that this Glu519 is important for AtCNGC11/12 channel function, proving that the occurrence of cpr22 phenotypes requires active channel function of AtCNGC11/12. Additionally, Glu519 was also found to be important for the function of the wild‐type channel AtCNGC12. Computational structural modeling and in vitro cAMP‐binding assays suggest that Glu519 is a key residue for the structural stability of AtCNGCs and contributes to the interaction of the cyclic nucleotide‐binding domain and the C‐linker domain, rather than the binding of cAMP. Furthermore, a mutation in the α‐subunit of the human cone receptor CNGA3 that causes total color blindness aligned well to the position of Glu519 in AtCNGC11/12. This suggests that AtCNGC11/12 suppressors could be a useful tool for discovering important residues not only for plant CNGCs but also for CNGCs in general.
Efficient virus‐induced gene silencing in Arabidopsis using a ‘one‐step’ TYMV‐derived vector
Authors: Pflieger Stéphanie , Blanchet Sandrine , Camborde Laurent , Drugeon Gabrièle , Rousseau Alice , Noizet Mildred , Planchais Séverine , Jupin Isabelle 
Published: July 2008

SummaryVirus‐induced gene silencing (VIGS) is an important tool for the analysis of gene function in plants. This technique exploits recombinant viral vectors harbouring fragments of plant genes in their genome to generate double‐stranded RNAs that initiate homology‐dependent silencing of the target gene. Several viral VIGS vectors have already been successfully used in reverse‐genetics studies of a variety of processes occurring in plants. Here, we show that a viral vector derived from Turnip yellow mosaic virus (TYMV) has the ability to induce VIGS in Arabidopsis thaliana, accession Col‐0, provided that it carries an inverted‐repeat fragment of the target gene. Robust and reliable gene silencing was observed when plants were inoculated simply by abrasion with intact plasmid DNA harbouring a cDNA copy of the viral genome, thus precluding the need for in vitro transcription, biolistic or agroinoculation procedures. Our results indicate that a 76 bp fragment is sufficient to cause gene silencing in leaves, stems and flowers, and that the TYMV‐derived vector also has the ability to target genes expressed in meristematic tissues. The VIGS vector described here may thus represent an ideal tool for improving high‐throughput functional genomics in Arabidopsis.
Novel clades of chromodomain‐containing Gypsy LTR retrotransposons from mosses (Bryophyta)
Authors: Novikova Olga , Mayorov Vladimir , Smyshlyaev Georgiy , Fursov Michail , Adkison Linda , Pisarenko Olga , Blinov Alexander 
Published: July 2008

SummaryRetrotransposons are the major component of plant genomes. Chromodomain‐containing Gypsy long terminal repeat (LTR) retrotransposons are widely distributed in eukaryotes. Four distinct clades of chromodomain‐containing Gypsy retroelements are known from the vascular plants: Reina, CRM, Galadriel and Tekay. At the same time, almost nothing is known about the repertoire of LTR retrotransposons in bryophyte genomes. We have combined a search of chromodomain‐containing Gypsy retroelements in Physcomitrella genomic sequences and an experimental investigation of diverse moss species. The computer‐based mining of the chromodomain‐containing LTR retrotransposons allowed us to describe four different elements from Physcomitrella. Four novel clades were identified that are evolutionarily distinct from the chromodomain‐containing Gypsy LTR retrotransposons of other plants.
Plant stress granules and mRNA processing bodies are distinct from heat stress granules
Authors: Weber Christian , Nover Lutz , Fauth Markus 
Published: July 2008

SummarySimilar to the situation in mammalian cells and yeast, messenger ribonucleo protein (mRNP) homeostasis in plant cells depends on rapid transitions between three functional states, i.e. translated mRNPs in polysomes, stored mRNPs and mRNPs under degradation. Studies in mammalian cells showed that whenever the dynamic exchange of the components between these states is disrupted, stalled mRNPs accumulate in cytoplasmic aggregates, such as stress granules (SGs) or processing bodies (PBs). We identified PBs and SGs in plant cells by detection of DCP1, DCP2 and XRN4, as marker proteins for the 5′→3′ mRNA degradation pathway, and eIF4E, as well as the RNA binding proteins RBP47 and UBP1, as marker proteins for stored mRNPs in SGs. Cycloheximide‐inhibited translation, stress treatments and mutants defective in mRNP homeostasis were used to study the dynamic transitions of mRNPs between SGs and PBs. SGs and PBs can be clearly discriminated from the previously described heat stress granules (HSGs), which evidently do not contain mRNPs. Thus, the role of HSGs as putative mRNP storage sites must be revised.
Relationships between crop yield and weed time of emergence/removal: modelling and parameter stability across environments
Authors: BERTI A , SATTIN M , BALDONI G , DEL PINO A M , FERRERO A , MONTEMURRO P , TEI F , VIGGIANI P , ZANIN G 
Published: July 2008

SummarySeventeen Italian experiments relating to maize, soyabean and durum wheat were used to analyse the variability of duration of tolerated competition (DTC) and weed‐free period (WFP) curves across reasonably homogeneous areas. The data sets were analysed by regression analysis using four models relating yield loss to weed density, time of emergence and removal. These models differ in the way they account for the effect of time of weed removal on potential competitiveness. A sigmoidal relationship between these two variables appears necessary. The model with the best overall performance was then used to test the stability of the parameters that give the shape of the curve in relation to time of emergence and removal. This was done by comparing a full model with shape parameters specific to each experiment and a reduced model with a common set of parameters for all the experiments referring to a specific crop. For all three crops, the residual sum of squares of the reduced model did not increase significantly, indicating that, across tested environments, the yield loss caused by mixed weed infestations can be expressed by a single set of parameters relating weed competitivity to time of emergence and removal. For a given area, it should therefore be possible to predict yield loss on the basis of a quite limited set of experiments, thus greatly simplifying the development and use of decision support systems (DSS).
A critique of studies evaluating glyphosate effects on diseases associated with Fusarium spp.
Authors: POWELL J R , SWANTON C J 
Published: July 2008

SummaryWith the large‐scale adoption of glyphosate‐resistant crops in North America, there are concerns that non‐target microbial populations might be affected by increased frequency of glyphosate use. Stimulation of fungal species associated with crop diseases, including Fusarium spp., has been observed in laboratory and glasshouse experiments. Although field surveys in Saskatchewan detected positive associations between the incidence of Fusarium head blight and application of glyphosate formulations, few field experiments have been successful at demonstrating a stimulatory effect of glyphosate on crop diseases, including diseases associated with Fusarium spp. Taken at face value, there is little evidence from experimental field trials to support a causative link between glyphosate and crop diseases associated with Fusarium spp. However, we are concerned that the experimental field trials investigating links between glyphosate and Fusarium spp. are not representative of interactions that occur under actual farming conditions. In addition, inadequate consideration may have been given to microbial ecology during the design and maintenance of these experimental field trials. At this time, there is insufficient evidence to prove or disprove a link between glyphosate and crop diseases associated with Fusarium spp. and this area should receive high research priority, given the rapid and widespread increase in glyphosate use.
Desmodium species and associated biochemical traits for controlling Striga species: present and future prospects
Authors: KHAN Z R , PICKETT J A , HASSANALI A , HOOPER A M , MIDEGA C A O 
Published: July 2008

SummaryWe discovered serendipitously a new and highly effective intervention against Striga spp., including Striga hermonthica (African witchweed), in cereals, which involves intercropping with cattle fodder legumes, Desmodium spp., including D. uncinatum. Although soil shading and additional nitrogen made some contribution to the reduction of S. hermonthica infestation, an allelopathic mechanism associated with the intercrop was a major factor. Root exudates of D. uncinatum contain novel flavonoid compounds, some of which stimulate germination of S. hermonthica and others dramatically inhibit its subsequent development, including radicle growth. Desmodium spp. have been developed as intercrops for both maize and sorghum and are now being evaluated for millet. From the experience with Desmodium spp., there is now the possibility for producing edible legumes suitable for intercropping with maize and other cereals to respond to a broader profile of farmer practices. These legumes would incorporate the powerful S. hermonthica controlling properties of D. uncinatum through feasible breeding programmes, with appropriate contributions from analytical chemistry to plant molecular genetics and biotechnology. In the longer term, it may also be possible to transfer genes associated with the allelopathic attributes to cereals themselves by heterologous gene expression, creating a new generation of parasitic weed‐free cereals.
Which future for weed science?
Authors: FERNANDEZ‐QUINTANILLA C , QUADRANTI M , KUDSK P , BÀRBERI P 
Published: July 2008

SummaryWeed science is a discipline dealing with a serious biotic threat capable of causing heavy economic, environmental or aesthetic losses to society. In the past, we have been successful in providing efficient, relatively cheap and safe technologies to manage this threat in a variety of situations. We have been able to provide practical advice and options for the end‐users based on a broad scientific knowledge. In order to continue this success, we need to anticipate the future and change faster than the world around us. Numerous opportunities are open to us. Weed science should enter the global climate change arena, getting involved in both mitigation (improving the carbon efficiency of agriculture and forestry) and adaptation (developing effective practices for the new crops, new production systems and the new weeds). We should find adequate answers to the new demands originating from the enlargement of farms and fields, the increased concern about the conservation of biodiversity and the growing consumer demands on food safety. We should look for new clients in non‐agricultural sectors, offering them our proved expertise and know‐how. We should try to exploit the new opportunities arising as a result of cross‐fertilisation of weed science with other disciplines. At the same time, we need to be aware of some threats: the dominance of short‐term commercial and political objectives in setting research agendas, the reduced R&D resources invested in the agrochemical industry in the development of new herbicides and the increasing ‘publish or perish’ pressure in the public research sector.
Allergic rhinitis management pocket reference 2008*
Authors: Bousquet J. , Reid J. , Van Weel C. , Baena Cagnani C. , Canonica G. W. , Demoly P. , Denburg J. , Fokkens W. J. , Grouse L. , Mullol K. , Ohta K. , Schermer T. , Valovirta E. , Zhong N. , Zuberbier T. 
Published: July 2008

Allergic rhinitis is a major chronic respiratory disease because of its prevalence, impacts on quality of life and work/school performance, economic burden, and links with asthma. Family doctors (also known as ‘primary care physicians’ or ‘general practitioners’) play a major role in the management of allergic rhinitis as they make the diagnosis, start the treatment, give the relevant information, and monitor most of the patients. Disease management that follows evidence‐based practice guidelines yields better patient results, but such guidelines are often complicated and may recommend the use of resources not available in the family practice setting. A joint expert panel of the World Organization of Family Doctors (Wonca), the International Primary Care Airways Group (IPAG) and the International Primary Care Respiratory Group (IPCRG), offers support to family doctors worldwide by distilling the globally accepted, evidence‐based recommendations from the Allergic Rhinitis and its Impact on Asthma (ARIA) initiative into this brief reference guide.This guide provides tools intended to supplement a thorough history taking and the clinician’s professional judgment in order to provide the best possible care for patients with allergic rhinitis. A diagnostic Questionnaire specifically focuses the physician’s attention on key symptoms and markers of the disease. When questionnaire responses suggest a diagnosis of allergic rhinitis, a Diagnosis Guide and a simple flowchart then lead the clinician through a series of investigations commonly available in primary care to support the diagnosis. In addition, key aspects of differential diagnosis are illuminated.According to ARIA, allergic rhinitis may be classified as Intermittent or Persistent, and as Mild or Moderate/Severe. The classification of rhinitis determines the treatment necessary, as set out in an ARIA flowchart included in this guide. The guide also includes information about the strength of evidence for efficacy of certain rhinitis treatments, a brief discussion of pediatric aspects, and a glossary of allergic rhinitis medications to assist the clinician in making medication choices for each individual patient. Finally, many patients with allergic rhinitis also have concomitant asthma, and this must be checked.The World Organization of Family Doctors has been delegated by WHO as the group that will be taking primary responsibility for education about chronic respiratory diseases among primary care physicians globally. This document will be a major resource in this educational program.
Severe asthma in childhood: assessed in 10 year olds in a birth cohort study*
Authors: Lang A. , Carlsen K. H. , Haaland G. , Devulapalli C. S. , Munthe‐Kaas M. , Mowinckel P. , Carlsen K. 
Published: July 2008

Background: Limited information is available regarding the prevalence of severe asthma in children. The present study aimed at investigating the prevalence of severe asthma in an urban child population; secondarily evaluating the applicability of the chosen definition by clinical characteristics.Methods: Children enrolled in the prospective birth cohort; the Environment and Childhood Asthma Study in Oslo; were reinvestigated at the age of 10 years (n = 1019). A representative population based cohort of 616 children [mean age 10.9 (SD 0.9) years] with lung function measurements at birth was used for prevalence estimates, whereas all 1019 children (154 with current asthma) attending the 10‐year follow‐up were included for verification of the definition of severe asthma. Clinical investigations included spirometry, tests of bronchial hyperresponsiveness, skin prick tests and exhaled nitric oxide. Severe asthma was defined as poorly controlled asthma despite treatment with ≥ 800 μg budesonide or equivalent; assessed by a detailed structured interview.Results: The population point prevalence at age 10 years of current severe asthma was 0.5% (three of 616) and among children with current asthma 4.5% (three of 67). The 10/154 children identified as suffering from severe asthma more often had severe bronchial hyperresponsiveness (PD20 methacholine <1 μmol) (60%vs 22%, P = 0.015), lower median forced expiratory volume in 1 s/forced vital capacity ratio (93%vs 99%, P = 0.04) and higher body mass index (mean BMI 22.3 vs 18.3, P < 0.001) than nonsevere current asthmatics.Conclusions: The prevalence of severe asthma was 0.5% in all 10‐year olds, and 4.5% among current asthmatics. The severe asthma definition applied in this study is supported by results of clinical investigations.
Paediatric anaphylaxis: a 5 year retrospective review
Authors: De Silva I. L. , Mehr S. S. , Tey D. , Tang M. L. K. 
Published: July 2008

Objective:  To describe the demographic characteristics, clinical features, causative agents, settings and administered therapy in children presenting with anaphylaxis.Methods:  This was a retrospective case note study of children presenting with anaphylaxis over a 5‐year period to the Emergency Department (ED) at the Royal Children’s Hospital, Melbourne.Results:  One‐hundred and twenty‐three cases of anaphylaxis in 117 patients were included. There was one death. The median age of presentation was 2.4 years. Home was the most common setting (48%) and food (85%) the most common trigger. Peanut (18%) and cashew nut (13%) were the most common cause of anaphylaxis. The median time from exposure to anaphylaxis for all identifiable agents was 10 min. The median time from onset to therapy was 40 min. Respiratory features were the principal presenting symptoms (97%). Seventeen per cent of subjects had experienced anaphylaxis previously.Conclusions:  This is the largest study of childhood anaphylaxis reported. Major findings are that most children presenting to the ED with anaphylaxis are first‐time anaphylactic reactions and the time to administration of therapy is often significantly delayed. Most reactions occurred in the home. Peanut and cashew nut were the most common causes of anaphylaxis in this study population, suggesting that triggers for anaphylaxis in children have not changed significantly over the last decade.