AtAMT1;4, a Pollen-Specific High-Affinity Ammonium Transporter of the Plasma Membrane in Arabidopsis

Pollen represents an important nitrogen sink in flowers to ensure pollen viability. Since pollen cells are symplasmically isolated during maturation and germination, membrane transporters are required for nitrogen import across the pollen plasma membrane. This study describes the characterization of the ammonium transporter AtAMT1;4, a so far uncharacterized member of the Arabidopsis AMT1 family, which is suggested to be involved in transporting ammonium into pollen. The AtAMT1;4 gene encodes a functional ammonium transporter when heterologously expressed in yeast or when overexpressed in Arabidopsis roots. Concentration-dependent analysis of 15N-labeled ammonium influx into roots of AtAMT1;4-transformed plants allowed characterization of AtAMT1;4 as a high-affinity transporter with a Km of 17 μM. RNA and protein gel blot analysis showed expression of AtAMT1;4 in flowers, and promoter–gene fusions to the green fluorescent protein (GFP) further defined its exclusive expression in pollen grains and pollen tubes. The AtAMT1;4 protein appeared to be localized to the plasma membrane as indicated by protein gel blot analysis of plasma membrane-enriched membrane fractions and by visualization of GFP-tagged AtAMT1;4 protein in pollen grains and pollen tubes. However, no phenotype related to pollen function could be observed in a transposon-tagged line, in which AtAMT1;4 expression is disrupted. These results suggest that AtAMT1;4 mediates ammonium uptake across the plasma membrane of pollen to contribute to nitrogen nutrition of pollen via ammonium uptake or retrieval

One-Dimensional Copper(II) Coordination Polymer as an Electrocatalyst for Water Oxidation

Karadas, Ferdi/0000-0001-7171-9889WOS: 000394144300010Although cobalt-based heterogeneous catalysts are the central focus in water oxidation research, interest in copper-based water oxidation catalysts has been growing thanks the great abundance of copper and its biological relevance. Several copper oxides have recently been reported to be active catalysts for water oxidation. in this study, a heterogeneous copper-based water oxidation catalyst that is not an oxide has been reported for the first time. Single-crystal XRD studies indicate that the compound is a one-dimensional coordination compound incorporating copper paddle-wheel units connected through phosphine dioxide ligands. the catalyst exhibits an onset potential of 372mV at pH10.2, whereas an overpotential of only 563mV is required to produce a current density of 1mAcm(-2). in addition to cyclic voltammetric and chronoamperometric studies, an investigation into the effect of pH on the catalytic activity and the robustness of the catalyst using long-term bulk electrolysis (12h) is presented.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [214Z095]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1929B011500059]The authors thank the Scientific and Technological Research Council of Turkey (TUBITAK) for financial support (Project No. 214Z095). E.U. thanks TUBITAK for support (Project 1929B011500059)

Precision genetic modifications: a new era in molecular biology and crop improvement

Recently, the use of programmable DNA-binding proteins such as ZFP/ZFNs, TALE/TALENs and CRISPR/Cas has produced unprecedented advances in gene targeting and genome editing in prokaryotes and eukaryotes. These advances allow researchers to specifically alter genes, reprogram epigenetic marks, generate site-specific deletions and potentially cure diseases. Unlike previous methods, these precision genetic modification techniques (PGMs) are specific, efficient, easy to use and economical. Here we discuss the capabilities and pitfalls of PGMs and highlight the recent, exciting applications of PGMs in molecular biology and crop genetic engineering. Further improvement of the efficiency and precision of PGM techniques will enable researchers to precisely alter gene expression and biological/chemical pathways, probe gene function, modify epigenetic marks and improve crops by increasing yield, quality and tolerance to limiting biotic and abiotic stress conditions

Cardiac ruptures following myocardial infarction in medicolegal cases

Objective: Characteristics of legal autopsy cases with cardiac rupture following myocardial infarction are investigated in this retrospective observational study and the results are compared with a control group consisting of acute myocardial infarction cases without rupture

Resources for Reverse Genetics Approaches in Arabidopsis thaliana

Uelker B, Weisshaar B. Resources for Reverse Genetics Approaches in Arabidopsis thaliana. In: Schmidt R, Bancroft I, eds. Genetics and Genomics of the Brassicaceae. Heidelberg, Germany: Springer; 2011: 527-560

Evaluation of clinical characteristics, diagnosis and management in childhood immune thrombocytopenic purpura: a single center's experience

purpura (ITP) are controversial. We reviewed the files of 162 children with ITP to evaluate clinical characteristics, response to treatment and outcome. History of antecedent infection, vaccination and serologic evidence for acute viral infection were present in 48%, 5% and 17% of the patients, respectively. At diagnosis, two-thirds of the patients had a platelet count of < 10,000/mu 1 but only 10% had major bleedings. Intracranial hemorrhage was seen in two patients (1.2%) with a mortality rate of 0.6%. Sixteen percent developed chronic ITP. The rate of platelet recovery with mega-dose methylprednisolone (30 mg/kg/d for 3 and 20 mg/kg/d for 4 days) was similar to that obtained with intravenous immunoglobulin or oral prednisolone. Four of seven patients with ITP responded to splenectomy. These data show that mode of treatment has no effect on the clinical course and prognosis of childhood ITP

Therapeutic concentrations of tacrolimus do not interfere with endothelial nitric oxide synthesis in rat thoracic aortas and coronary arteries

WOS: 000250415100008PubMed ID: 18049307This study aimed to investigate the potential effect of in vivo administration of immunosuppressive agent FK-506 (tacrolimus) on the endothelial function of rat thoracic aortas with respect to nitric oxide (NO) synthesis. In vitro effect of the drug on NO synthesis in cultured rat coronary microvascular endothelial cells (CMEC) was also studied. In vivo administration of tacrolimus (1 mg/kg/d, intramuscular) to rats for 14 days resulted in decreased relaxant responses to the higher concentrations (1 to 30 mu M) of acetylcholine in the aortas; however, responses to calcium ionophore A23187, sodium nitroprusside, L-arginine, and L-NAME did not change significantly. No changes were observed in phenylephrine-induced contractions in endothelium-denuded or -intact preparations. Administration of the vehicle for 14 days did not affect these parameters. In order to evaluate the in vitro effect of tacrolimus on NO release, CMEC isolated from rat hearts were incubated with either tacrolimus (0.01, 0.1 mu M) or the vehicle. Basal, calcium ionophore-stimulated, or interleukin-IP-induced NO synthesis was determined by measuring total nitrite in the media. Neither tacrolimus nor the vehicle changed nitrite accumulation. It has been concluded that therapeutic concentrations of tacrolimus do not alter NO production in rat thoracic aorta or cultured CMEC however, it impairs relaxant responses of rat aorta induced by higher concentrations of acetylcholine, possibly through changes in the downstream of receptor activation or through an imbalance between endothelium-dependent relaxant and contracting factors within the endothelium in favor of the contracting factor(s)