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Metal Homeostasis (metal + homeostasi)

Distribution by Scientific Domains
Life Sciences57%

Selected Abstracts

Metals and oxidative homeostasis in Alzheimer's disease

DRUG DEVELOPMENT RESEARCH, Issue 3 2002
George Perry
Abstract Oxidative damage to every class of biological macromolecule has been characterized in Alzheimer's disease. Abnormalities in iron and copper metabolism are also being implicated as playing a crucial role in neurodegenerative disease pathogenesis. Metal homeostasis as it pertains to alterations in brain function in neurodegenerative diseases is reviewed here with its relationship to oxidative stress. While there is documented evidence for alterations in transition metal homeostasis, redox-activity, and localization, it is also important to realize that alterations in specific copper- and iron-containing metalloenzymes also contribute to the neurodegenerative process. These changes offer the opportunity to identify pathways where modification of the disease process can offer new routes for clinical efficacy, from gene therapy to use of antioxidant and chelating drugs. Drug Dev. Res. 56:293,299, 2002. © 2002 Wiley-Liss, Inc. [source]

Microbial functional structure of Montastraea faveolata, an important Caribbean reef-building coral, differs between healthy and yellow-band diseased colonies

ENVIRONMENTAL MICROBIOLOGY, Issue 2 2010
Nikole E. Kimes
Summary A functional gene array (FGA), GeoChip 2.0, was used to assess the biogeochemical cycling potential of microbial communities associated with healthy and Caribbean yellow band diseased (YBD) Montastraea faveolata. Over 6700 genes were detected, providing evidence that the coral microbiome contains a diverse community of archaea, bacteria and fungi capable of fulfilling numerous functional niches. These included carbon, nitrogen and sulfur cycling, metal homeostasis and resistance, and xenobiotic contaminant degradation. A significant difference in functional structure was found between healthy and YBD M. faveolata colonies and those differences were specific to the physical niche examined. In the surface mucopolysaccharide layer (SML), only two of 31 functional categories investigated, cellulose degradation and nitrification, revealed significant differences, implying a very specific change in microbial functional potential. Coral tissue slurry, on the other hand, revealed significant changes in 10 of the 31 categories, suggesting a more generalized shift in functional potential involving various aspects of nutrient cycling, metal transformations and contaminant degradation. This study is the first broad screening of functional genes in coral-associated microbial communities and provides insights regarding their biogeochemical cycling capacity in healthy and diseased states. [source]

The genetics of essential metal homeostasis during development

GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 4 2008
Taiho Kambe
Zinc is one of the essential metals that along with copper and iron are essential for embryonic and postnatal development and homeostasis. See the review by Kambe et al. in this issue. [source]

Characterization of the Arabidopsis metallothionein gene family: tissue-specific expression and induction during senescence and in response to copper

NEW PHYTOLOGIST, Issue 2 2003
Woei-Jiun Guo
Summary ,Expression and regulation of Arabidopsis metallothionein (MT) genes were investigated to examine the functions of MTs in plants. ,To examine the tissue-specific expression of MT genes, GUS reporter gene activity driven by promoters of MT1a, MT2a, MT2b and MT3 was analysed in transgenic plants. ,MT1a and MT2b are expressed in the phloem of all organs and are copper (Cu)-inducible; MT2a and MT3, by contrast, are expressed predominantly in mesophyll cells and are also induced by Cu in young leaves and at root tips. Expression of MT genes is highly induced by Cu in trichomes and increases during senescence. Expression of MT4 genes is restricted to seeds. ,We propose that plant MTs have distinct functions in heavy metal homeostasis, especially for Cu: MT1a and MT2b are involved in the distribution of Cu via the phloem, while MT2a and MT3 chaperone excess metals in mesophyll cells and root tips. These functional capabilities may allow MTs to play a role in mobilization of metal ions from senescing leaves and the sequestration of excess metal ions in trichomes. [source]

TcYSL3, a member of the YSL gene family from the hyper-accumulator Thlaspi caerulescens, encodes a nicotianamine-Ni/Fe transporter

THE PLANT JOURNAL, Issue 1 2007
Delphine Gendre
Summary The two main features of plant hyper-accumulator species are the massive translocation of heavy metal ions to the aerial parts and their tolerance to such high metal concentrations. Recently, several lines of evidence have indicated a role for nicotianamine (NA) in metal homeostasis, through the chelation and transport of NA,metal complexes. The function of transport of NA,metal chelates, required for the loading and unloading of vessels, has been assigned to the Yellow Stripe 1 (YSL)-Like family of proteins. We have characterized three YSL genes in Thlaspi caerulescens in the context of hyper-accumulation. The three YSL genes are expressed at high rates compared with their Arabidopsis thaliana homologs but with distinct patterns. While TcYSL7 was highly expressed in the flowers, TcYSL5 was more highly expressed in the shoots, and the expression of TcYSL3 was equivalent in all the organs tested. In situ hybridizations have shown that TcYSL7 and TcYSL5 are expressed around the vasculature of the shoots and in the central cylinder in the roots. The exposure to heavy metals (Zn, Cd, Ni) does not affect the high and constitutive expression of the TcYSL genes. Finally, we have demonstrated by mutant yeast complementation and uptake measurements that TcYSL3 is an Fe/Ni,NA influx transporter. This work provides therefore molecular, histological and biochemical evidence supporting a role for YSL transporters in the overall scheme of NA and NA,metal, particularly NA,Ni, circulation in a metal hyper-accumulator plant. [source]

Expression, purification, crystallization and preliminary X-ray analysis of an archaeal protein homologous to plant nicotianamine synthase

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2008
Cyril Dreyfus
In plants, nicotianamine synthase (NAS) plays a key role in metal homeostasis as it catalyzes the formation of nicotianamine, an important iron and nickel chelator and a precursor of plant phytosiderophores. Here, the crystallization of a protein from Methanothermobacter thermoautotrophicus (MTH675; referred to here as MtNAS) that appears to be homologous to plant NAS is reported. Purification of this protein showed a monomer,dimer equilibrium that could be displaced by using a reducing agent such as DTT. Crystals belonging to space group P212121 and containing dimers of MtNAS were grown by the vapour-diffusion method using polyethylene glycol 3350 as precipitant. A complete native X-ray data set was collected to 1.7,Å resolution at a synchrotron source. [source]