Knock-out of Arabidopsis metal transporter gene IRT1 results in iron deficiency accompanied by cell differentiation defects

IRT1 and IRT2 are members of the Arabidopsis ZIP metal transporter family that are specifically induced by iron deprivation in roots and act as heterologous suppressors of yeast mutations inhibiting iron and zinc uptake. Although IRT1 and IRT2 are thought to perform redundant functions as root-specific metal transporters, insertional inactivation of the IRT1 gene alone results in typical symptoms of iron deficiency causing severe leaf chlorosis and lethality in soil. The irt1 mutation is characterized by specific developmental defects, including a drastic reduction of chloroplast thylakoid stacking into grana and lack of palisade parenchyma differentiation in leaves, reduced number of vascular bundles in stems, and irregular patterns of enlarged endodermal and cortex cells in roots. Pulse labeling with 59Fe through the root system shows that the irt1 mutation reduces iron accumulation in the shoots. Short-term labeling with 65Zn reveals no alteration in spatial distribution of zinc, but indicates a lower level of zinc accumulation. In comparison to wild-type, the irt1 mutant responds to iron and zinc deprivation by altered expression of certain zinc and iron transporter genes, which results in the activation of ZIP1 in shoots, reduction of ZIP2 transcript levels in roots, and enhanced expression of IRT2 in roots. These data support the conclusion that IRT1 is an essential metal transporter required for proper development and regulation of iron and zinc homeostasis in Arabidopsis.

Iodine ages of pore water at Hydrate Ridge, Cascadian continental margin

Hydrate Ridge off the coast of Oregon, USA, is a prime example for gas hydrate occurrences in active margin settings. It is part of the Cascadia Margin and was the focus of Ocean Drilling Program (ODP) Leg 204, which successfully recovered fluids from nine sites from the southern part of the ridge. Iodide concentrations in pore fluids associated with gas hydrates are strongly enhanced, by factors up to 5000 compared to seawater, which allows the use of this biophilic element as tracer for organic source regions. We applied the cosmogenic isotope 129I (T1/2=15.7 Ma) system to determine the age of the organic source formation responsible for the iodide enrichment. In all sites at ODP Leg 204, 129I/I ratios were found to decrease with depth to values around 250x10**-15, corresponding to minimum ages of 40 Ma, but in several sites, maxima in the 129I/I ratios point to the local addition of young iodide. The results indicate that a large amount of iodide was derived from deep accreted sediments of Eocene age, and that additional source regions provide iodide of Late Miocene age. The presence of old iodide in the pore waters suggests that fluid pathways are open to allow transport over large distances into the gas hydrate fields. The strong correlation between iodide and methane in hydrate fields coupled with the similarity in transport parameters in aqueous solutions suggests that a large fraction of methane in gas hydrates also has old sources and is transported into the present locations from source regions of Eocene age.

Managing gonadotropin deficiency /

Shipping list no.: 86-609-P.

Radioactive iodine therapy for inpatients.

Mode of access: Internet.

Applications of iodine-123 in nuclear medicine : proceedings of a conference held in Rockville, Maryland, May 19-20, 1975.

Mode of access: Internet.

A guide to the Mental deficiency act, 1913 : containing a legal and general exposition of the act, with suggestions to local authorities, managers and others for the organization and administration of the work dealing with the mental defective /

Mode of access: Internet.

Food-chain relationships of iodine-131 in Nevada following the Sedan Test of July 1962 /

Prepared for the U.S Atomic Energy Commission.

Iodine inhalation study for Project Sedan : July 6, 1962 /

Final report.

Food-chain relationships of iodine-131 following two nuclear tests in Nevada,

Mode of access: Internet.

Devitalization of microorganisms by iodine,

Cover title.

The 1990 Farm Act and the 1990 Budget Reconciliation Act : how U.S. farm policy mechanisms will work under the new legislation : includes description of target prices, loan rates, deficiency payments, and new planting flexibility provisions.

Mode of access: Internet.

American journal of mental deficiency.

Includes the association's conference proceedings and addresses.

The hydrolysis of Iodine and a reaction with "Propanol".

Mode of access: Internet.

Chlorine and chlorine products, including the manufacture of bleaching powder, hypochlorites, chlorates, etc., with sections on bromine, iodine, and hydrofluoric acid

"Literature" at the beginning of most chapters.

Removal of radioactive iodine by laboratory trickling filters /

Mode of access: Internet.