Sub-cellular Location of Mercury in Yeast Grown in the Presence of Mercuric Chloride

Abstract

The distribution of 203Hg in Saccharomyces cerevisiae grown in the presence of mercuric chloride has been examined by physical and chemical fractionation procedures and autoradiography. The major fraction of the bound mercury is tightly bound to the wall. A significant quantity of mercury penetrates to the cytoplasm but only a minor fraction is present as low molecular weight components. The wallassociated mercury is not readily released by extraction with sodium hydroxide or ethylenediamine but a major fraction is solubilized by Pronase and Helicase treatment. Isolated walls are capable of binding their own weight of mercury to highaffinity adsorption sites. The major role of the cell envelope in the in vivo binding of mercury and the penetration to the cytoplasm of mercury was confirmed by au t oradi ograph y .

Uptake and Distribution of Mercury within Higher Plants

“…Alternatively it may represent degrees of Hg binding to a wide spectrum of material in plants. Murray and Kidby (1975) have shown that a significant quantity of Hg is tightly bound to the cell wall in Saccharomyces cerevisiae. In their experiments Hg was associated with the cell wall and was not easily released by various treatments.…”

“…Very little seems to be known about the relationships of mercury with plant systems although there have recently been some reasonable detailed studies on algae (Kamp-Nielsen 1971, Shieh and Barber 1973, Ben-Bassat and Mayer 1975 and other microorganisms (Murray and Kidby 1975). Much earlier work by Hitchcock and Zimmerman (1957) had shown that higher plants were sensitive to the pre-sence of vapours of mercury and its compounds under certain conditions.…”

Uptake and cellular distribution of copper, cobalt and cadmium in strains of Saccharomyces cerevisiae cultured on elevated concentrations of these metals

“…Sequestration can occur as extracellular precipitation, for example as sulphide [16], partitioning among cell compartments or binding to specific intracellular molecules such as metallothioneins [17] and polyphosphates [8]. Partitioning into cell components such as the wall has been implicated in metal resistance of yeast to Hg [18] and the vacuole is also regarded as a compartment for the storage of potentially harmful materials including Mn 2+ [19]. There is little information on the role of compartmentation for other potentially toxic metals such as Co and Cu.…”

Different Distribution of Cd2+ between Cd-sensitive and Cd-resistant Strains of Saccharomyces cerevisiae

“…1968). The subcellular distribution of heavy metal ions accumulated by yeast can be categorized into the following two types: (1) the soluble type, such as Cul+ and Mn2+, most of which occur in the cytosol fraction (Imahara et a/., 1978;Bianchi et a/., 1981); and (2) the bound type, such as Hg'+, which exist as the bound form in the cell membrane or the cell wall (Murray & Kidby, 1975;Brown & Smith, 1977). Furthermore, Bianchi et al (1981) have reported that when Saccharomyes cerecesiae adapted to a toxic environment containing Mn'+, the subcellular distribution of this ion changed from the soluble to the insoluble type.…”