Bioactive trace metals

Bruland, K. W., Donat, J. R. and Hutchins, D. A. (1991). Interactive influence of bioactive trace metals on biological production in oceanic waters, Limnol. Oceanogr., 36, 1555-1577. 

All experiments to date have involved the injection of an iron sulfate solution into the ship s wake to achieve rapid dilution and dispersion throughout the mixed layer (Figure 6). The rationale for using ferrous sulfate involved the following considerations (1) ferrous sulfate is the most likely form of iron to enter the oceans via atmospheric deposition (2) it is readily soluble (initially) (3) it is available in a relatively pure form so as to reduce the introduction of other potentially bioactive trace metals and (4) its counterion (sulfate) is ubiquitous in sea water and not likely to produce confounding effects. Although mixing models indicate that Fe(II) carbonate may reach insoluble levels in the ship s wake, rapid dilution reduces this possibility. 

Wells.M. L.,and Bruland,K.W. (1999). An improved method for rapid preconcentration and determination of bioactive trace metals in seawater using solid phase extraction and high resolution inductively coupled plasma mass spectrometry. Mar. Chem. 63(1), 145. 

Intracellular distribution of essential transition metals is mediated by specific metallochaperones and transporters localized in endomembranes. In other words, the major processes involved in hyperaccumulation of trace metals from the contaminated medium to the shoots by hyperaccumulators as proposed by Yang et al. (2005) include bioactivation of metals in the rhizosphere through root-microbial interaction enhanced uptake by metal transporters in the plasma membranes detoxification of metals by distributing metals to the apoplasts such as binding to cell walls and chelation of metals in the cytoplasm with various ligands (such as PCs, metallothioneins, metal-binding proteins) and sequestration of metals into the vacuole by tonoplast-located transporters. 

Bioactive Ihice Metals and Trace Metal Stable Isotopes... 

Dissolved iron provides an example of a bioactive, essential trace metal that is depleted in oceanic surface waters to such an extent that it has been estimated to be the limiting nutrient in —40% of the world s oceans (Moore et al., 2002). In particular, iron has been shown to be the limiting nutrient in the HNLC regions of the Southern Ocean, the equatorial Pacific, and the subarctic Pacific (Martin et al., 1994). Not only does iron exist at extremely low concentrations in... 

As a possible method of concentrating trace amounts of bioactive organic compounds occurring in the hydrosphere, adsorption properties of various compounds have been explored by employing hydrous metal oxides as the adsorbents. To date, a family of organophosphoms compounds and carbonic acids were adsorbed onto hydrous iron oxide, along with the adsoi ption of monosaccharides onto hydrous zirconium oxide. 

Ascorbic acid (Vitamin C H A) has been widely used in pharmaceutical, chemical, cosmetic and food industry because of its bioactive and antioxidant properties [1]. Cu (II) ion is important nutrients found in many food and pharmaceutical products. Traces of transition metal ions like as Cu(II) ion also acts as catalyst in the oxidation... 

There are many review articles concerning application of USE in food technology [57] and for isolation of bioactive substances from herbs and other plant materials [58], as well as leaching of heavy metals from environmental and industrial samples [59]. Application of ultrasound during sequential extraction of trace elements significantly shortens the whole procedure however, for satisfactory efficiency it is necessary to increase the temperature and modify the matrix. 

---