A noncanonical auxin-sensing mechanism is required for organ morphogenesis in Arabidopsis

Tissue patterning in multicellular organisms is the output of precise spatio–temporal regulation of gene expression coupled with changes in hormone dynamics. In plants, the hormone auxin regulates growth and development at every stage of a plant's life cycle. Auxin signaling occurs through binding of the auxin molecule to a TIR1/AFB F-box ubiquitin ligase, allowing interaction with Aux/IAA transcriptional repressor proteins. These are subsequently ubiquitinated and degraded via the 26S proteasome, leading to derepression of auxin response factors (ARFs). How auxin is able to elicit such a diverse range of developmental responses through a single signaling module has not yet been resolved. Here we present an alternative auxin-sensing mechanism in which the ARF ARF3/ETTIN controls gene expression through interactions with process-specific transcription factors. This noncanonical hormone-sensing mechanism exhibits strong preference for the naturally occurring auxin indole 3-acetic acid (IAA) and is important for coordinating growth and patterning in diverse developmental contexts such as gynoecium morphogenesis, lateral root emergence, ovule development, and primary branch formation. Disrupting this IAA-sensing ability induces morphological aberrations with consequences for plant fitness. Therefore, our findings introduce a novel transcription factor-based mechanism of hormone perception in plants. Note that there is a CORRIGENDUM to this article: http://eprints.whiterose.ac.uk/132306/ http://genesdev.cshlp.org/content/31/17/1821.ful

Effectiveness of distributed temperature measurements for early detection of piping in river embankments

Abstract. Internal erosion is the cause of a significant percentage of failure and incidents involving both dams and river embankments in many countries. In the past 20 years the use of fibre-optic Distributed Temperature Sensing (DTS) in dams has proved to be an effective tool for the detection of leakages and internal erosion. This work investigates the effectiveness of DTS for dike monitoring, focusing on the early detection of backward erosion piping, a mechanism that affects the foundation layer of structures resting on permeable, sandy soils. The paper presents data from a piping test performed on a large-scale experimental dike equipped with a DTS system together with a large number of accompanying sensors. The effect of seepage and piping on the temperature field is analysed, eventually identifying the processes that cause the onset of thermal anomalies around piping channels and thus enable their early detection. Making use of dimensional analysis, the factors that influence this thermal response of a dike foundation are identified. Finally some tools are provided that can be helpful for the design of monitoring systems and for the interpretation of temperature data

UNRAVELING THE ROLE OF BPC PROTEINS IN INFLORESCENCE AND FLOWER DEVELOPMENT IN A. THALIANA

BPC proteins belong to a small plant specific family of transcription factors and they share functional similarities with the GAGA ASSOCIATED FACTOR (GAF) of Drosophila melanogaster. In Arabidopsis thaliana, there are seven BPs genes, although BPC5 is considered a pseudogene. Except BPC5, BPC genes are ubiquitously expressed in all plant tissues throughout development and this overlap in expression could suggest that BPCs act redundantly. The C-terminal domain of BPC proteins facilitates binding to DNA at GA-rich sequences and for BPC1, a consensus binding site has been proposed. However, little is known about their function in gene regulation and INNER NO OUTER, SEEDSTICK and LEAFY COTYLEDON2 are the only BPC target genes identified until now. To study BPC function in vivo, we have now constructed bpc1 bpc2 bpc3 triple mutants, which develop inflorescences comprising more flowers than wild-type plants, their phyllotaxis is altered and flowers develop extra floral organs. These features could be linked to meristem size and activity: it is well known that plants with bigger and/or more active meristems produce higher number of flowers and floral organs respect to wild-type. An involvement of BPC regulators in meristem maintenance has not been uncovered yet, however the BBR factor (the BPC homolog in barley) binds and regulates the BKN3 gene, the barley homolog of Arabidopsis SHOOTMERISTEMLESS (STM). In Arabidopsis, STM is involved in meristem maintenance and activity and it is also involved in the cytokinin pathway, a class of plant hormones able to promote shoot meristem growth and maintenance. These data made it interesting to investigate the involvement of BPCs and their role in the cytokinin pathway

Role of cellular senescence and NOX4-mediated oxidative stress in systemic sclerosis pathogenesis.

Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and numerous internal organs and a severe fibroproliferative vasculopathy resulting frequently in severe disability and high mortality. Although the etiology of SSc is unknown and the detailed mechanisms responsible for the fibrotic process have not been fully elucidated, one important observation from a large US population study was the demonstration of a late onset of SSc with a peak incidence between 45 and 54 years of age in African-American females and between 65 and 74 years of age in white females. Although it is not appropriate to consider SSc as a disease of aging, the possibility that senescence changes in the cellular elements involved in its pathogenesis may play a role has not been thoroughly examined. The process of cellular senescence is extremely complex, and the mechanisms, molecular events, and signaling pathways involved have not been fully elucidated; however, there is strong evidence to support the concept that oxidative stress caused by the excessive generation of reactive oxygen species may be one important mechanism involved. On the other hand, numerous studies have implicated oxidative stress in SSc pathogenesis, thus, suggesting a plausible mechanism in which excessive oxidative stress induces cellular senescence and that the molecular events associated with this complex process play an important role in the fibrotic and fibroproliferative vasculopathy characteristic of SSc. Here, recent studies examining the role of cellular senescence and of oxidative stress in SSc pathogenesis will be reviewed

Schema-agnostic progressive entity resolution

Entity Resolution (ER) is the task of finding entity profiles that correspond to the same real-world entity. Progressive ER aims to efficiently resolve large datasets when limited time and/or computational resources are available. In practice, its goal is to provide the best possible partial solution by approximating the optimal comparison order of the entity profiles. So far, Progressive ER has only been examined in the context of structured (relational) data sources, as the existing methods rely on schema knowledge to save unnecessary comparisons: they restrict their search space to similar entities with the help of schema-based blocking keys (i.e., signatures that represent the entity profiles). As a result, these solutions are not applicable in Big Data integration applications, which involve large and heterogeneous datasets, such as relational and RDF databases, JSON files, Web corpus etc. To cover this gap, we propose a family of schema-agnostic Progressive ER methods, which do not require schema information, thus applying to heterogeneous data sources of any schema variety. First, we introduce two na\uefve schema-agnostic methods, showing that straightforward solutions exhibit a poor performance that does not scale well to large volumes of data. Then, we propose four different advanced methods. Through an extensive experimental evaluation over 7 real-world, established datasets, we show that all the advanced methods outperform to a significant extent both the na\uefve and the state-of-the-art schema-based ones. We also investigate the relative performance of the advanced methods, providing guidelines on the method selection

Kinematics of gaits in Bardigiano horses

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Class I BASIC PENTACYSTEINE factors regulate HOMEOBOX genes involved in meristem size maintenance

The BASIC PENTACYSTEINE (BCP) family is a poorly characterized plant transcription factor family of GAGA BINDING PROTEINS. In Arabidopsis, there are seven members (BPC1-7) that are broadly expressed, and they can potentially bind more than 3000 Arabidopsis GAGA-repeat-containing genes. To date, BPCs are known to be direct regulators of the INNER NO OUTER (INO), SEEDSTICK (STK), and LEAFY COTYLEDON 2 (LEC2) genes. Because of the high functional redundancy, neither single knockout nor double bpc mutant combinations cause aberrant phenotypes. The bpc1-2 bpc2 bpc3 triple mutant shows several pleiotropic developmental defects, including enlargement of the inflorescence meristem and flowers with supernumerary floral organs. Here, we demonstrated through expression analysis and chromatin immunoprecipitation assays that this phenotype is probably due to deregulation of the expression of the SHOOTMERISTEMLESS (STM) and BREVIPEDICELLUS/KNAT1 (BP) genes, which are both direct targets of BPCs. Moreover, we assigned a role to BPCs in the fine regulation of the cytokinin content in the meristem, as both ISOPENTENYLTRANSFERASE 7 (IPT7) and ARABIDOPSIS RESPONSE REGULATOR 7 (ARR7) genes were shown to be overexpressed in the bpc1-2 bpc2 bpc3 triple mutant

Ecotoxicity of hallachrome, an unusual 1-2 anthraquinone excreted by the infaunal polychaete Halla parthenopeia: evidence for a chemical defence?

Polychaetes play a prominent role in marine systems, but little is known about their secondary metabolites compared with other benthic taxa. In the present study, we investigated the toxicity of hallachrome, an unusual 1-2 anthraquinone identified from the skin of some polychaetes, including the Mediterranean infaunal species Halla parthenopeia. Under stress conditions, this worm releases a harmful purple mucus, whose noxious compounds were still unknown. We hypothesized that hallachrome also occurs in the purple mucus, giving rise to its color and toxicity. Soon after the production of the purple exudate, H. parthenopeia also secretes a harmless, transparent mucus, which pushes away the toxic one, suggesting protective functions for the worm itself. LC-MS and H-1-NMR analyses confirmed the presence of the pigment hallachrome in the purple mucus. The average concentration of the pigment in the purple mucus was about 310 mg L-1. Ecotoxicological bioassays on representative species of bacteria, protozoans, rotifers, crustaceans (Artemia franciscana) and polychaetes (Dinophilus gyrociliatus) revealed its severe toxic effects: LC50/EC(50)values ranged from 0.11-5.67 mg L-1. Hallachrome showed higher toxicity for A. franciscana than other naturally occurring anthraquinones. Tests on encapsulated embryos of D. gyrociliatus evidenced the ability of a mucus layer to limit hallachrome diffusion, confirming the protective role of the transparent mucus. Given the information available on polychaetes anti-predator strategies, hallachrome cannot be considered a consumer deterrent. However its toxicity and wide range of activity suggest chemical defensive functions against potential competitors, parasites and/or pathogens