Fluorescence-Tagged Transgenic Lines Reveal Genetic Defects in Pollen Growth—Application to the Eif3 Complex

BACKGROUND: Mutations in several subunits of eukaryotic translation initiation factor 3 (eIF3) cause male transmission defects in Arabidopsis thaliana. To identify the stage of pollen development at which eIF3 becomes essential it is desirable to examine viable pollen and distinguish mutant from wild type. To accomplish this we have developed a broadly applicable method to track mutant alleles that are not already tagged by a visible marker gene through the male lineage of Arabidopsis. METHODOLOGY/PRINCIPAL FINDINGS: Fluorescence tagged lines (FTLs) harbor a transgenic fluorescent protein gene (XFP) expressed by the pollen-specific LAT52 promoter at a defined chromosomal position. In the existing collection of FTLs there are enough XFP marker genes to track nearly every nuclear gene by virtue of its genetic linkage to a transgenic marker gene. Using FTLs in a quartet mutant, which yields mature pollen tetrads, we determined that the pollen transmission defect of the eif3h-1 allele is due to a combination of reduced pollen germination and reduced pollen tube elongation. We also detected reduced pollen germination for eif3e. However, neither eif3h nor eif3e, unlike other known gametophytic mutations, measurably disrupted the early stages of pollen maturation. CONCLUSION/SIGNIFICANCE: eIF3h and eIF3e both become essential during pollen germination, a stage of vigorous translation of newly transcribed mRNAs. These data delimit the end of the developmental window during which paternal rescue is still possible. Moreover, the FTL collection of mapped fluorescent protein transgenes represents an attractive resource for elucidating the pollen development phenotypes of any fine-mapped mutation in Arabidopsis

Penetration of the Stigma and Style Elicits a Novel Transcriptome in Pollen Tubes, Pointing to Genes Critical for Growth in a Pistil

Pollen tubes extend through pistil tissues and are guided to ovules where they release sperm for fertilization. Although pollen tubes can germinate and elongate in a synthetic medium, their trajectory is random and their growth rates are slower compared to growth in pistil tissues. Furthermore, interaction with the pistil renders pollen tubes competent to respond to guidance cues secreted by specialized cells within the ovule. The molecular basis for this potentiation of the pollen tube by the pistil remains uncharacterized. Using microarray analysis in Arabidopsis, we show that pollen tubes that have grown through stigma and style tissues of a pistil have a distinct gene expression profile and express a substantially larger fraction of the Arabidopsis genome than pollen grains or pollen tubes grown in vitro. Genes involved in signal transduction, transcription, and pollen tube growth are overrepresented in the subset of the Arabidopsis genome that is enriched in pistil-interacted pollen tubes, suggesting the possibility of a regulatory network that orchestrates gene expression as pollen tubes migrate through the pistil. Reverse genetic analysis of genes induced during pollen tube growth identified seven that had not previously been implicated in pollen tube growth. Two genes are required for pollen tube navigation through the pistil, and five genes are required for optimal pollen tube elongation in vitro. Our studies form the foundation for functional genomic analysis of the interactions between the pollen tube and the pistil, which is an excellent system for elucidation of novel modes of cell–cell interaction

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Anaphylaxis knowledge gaps and future research priorities: a consensus report

BACKGROUND: Despite a better understanding of the epidemiology, pathogenesis, and management of patients with anaphylaxis, there remain knowledge gaps. Enumerating and prioritizing these gaps would allow limited scientific resources to be directed more effectively. OBJECTIVE: To systematically describe and appraise anaphylaxis knowledge gaps and future research priorities based on their potential impact and feasibility. METHODS: We convened a 25-member multidisciplinary panel of anaphylaxis experts. Panelists formulated knowledge gaps/research priority statements in an anonymous electronic survey. Four anaphylaxis themed writing groups were formed to refine statements: 1) Population Science, 2) Basic & Translational Sciences, 3) Emergency Department Care/Acute Management, and 4) Long-Term Management Strategies & Prevention. Revised statements were incorporated into an anonymous electronic survey and panelists were asked to rate the impact and feasibility of addressing statements on a continuous 0-100 scale. RESULTS: The panel generated 98 statements across the four anaphylaxis themes: Population Science (29), Basic & Translational Sciences (27), Emergency Department Care/Acute Management (24), and Long-Term Management Strategies & Prevention (18). Median scores for impact and feasibility ranged from 50.0-95.0 and from 40.0-90.0. Key statements based on median rating for impact/feasibility included the need to refine anaphylaxis diagnostic criteria, identify reliable diagnostic, predictive, and prognostic anaphylaxis bioassays, develop clinical prediction models to standardize post-anaphylaxis observation periods and hospitalization criteria, and determine immunotherapy best practices. CONCLUSIONS: We identified and systematically appraised anaphylaxis knowledge gaps and future research priorities. This study reinforces the need to harmonize scientific pursuits to optimize the outcomes of patients with and at risk of anaphylaxis

A systems approach towards the stoichiometry-controlled hetero-assembly of nanoparticles

10.1038/ncomms1089Nature Communications17

The winner takes it all — Competitiveness of single nodes in globalized supply networks

Quantifying the importance and power of individual nodes depending on their position in socio-economic networks constitutes a problem across a variety of applications. Examples include the reach of individuals in (online) social networks, the importance of individual banks or loans in financial networks, the relevance of individual companies in supply networks, and the role of traffic hubs in transport networks. Which features characterize the importance of a node in a trade network during the emergence of a globalized, connected market? Here we analyze a model that maps the evolution of global connectivity in a supply network to a percolation problem. In particular, we focus on the influence of topological features of the node within the underlying transport network. Our results reveal that an advantageous position with respect to different length scales determines the competitiveness of a node at different stages of the percolation process and depending on the speed of the cluster growth