Cadmium ions, inhibition

Catalysis and inhibition of the electroreduction of cadmium ions at a partially blocked DM E by 1-butanol was... 

For cadmium, Weigel (1985 a, b) concluded that, in vitro, this metal inhibits photosynthesis mainly by interaction with several sites in the Calvin cycle and not by interaction with photochemical reactions located on the thylakoid membrane. In vitro studies showed a 90% inhibition of phosphoribulokinase (EC 2.7.1.18) by cadmium ions (Hurwitz et al., 1956). This element also inhibited light activation of the Calvin cycle enzymes glyceraldehyde-3-phosphate kinase (EC 1.2.1.13) and ribulose-5-phos-phate kinase (EC 2.7.1.19) in mesophyll protoplasts of Valerianella locusta (Weigel,... 

Reduction of active uptake in the cell cadmium resistance of Euglena gracilis strains was suggested to be the result of a membrane transport mechanism (inhibition of the membrane cadmium ion transport or increase of the cadmium exclusion mechanism Bariaud et al., 1985). 

The growth of the bacterium is inhibited by benzoic acid, sorbate, and sodium laurylate (Onysko et al., 1984), and nitrate at 50 mM inhibits completely the oxidation of ferrous ion by the bacterium (Eccleston et al., 1985). Although the bacterium is sensitive to chloride ion, it becomes resistant to 140 pM chloride ion by training (Shiratori and Sonta, 1993). The bacterium is fairly resistant to heavy metal ions its activity to oxidize ferrous ion is scarcely inhibited in the presence of 65 mM cupric ion, 100 mM nickel ion, 100 mM cobalt ion, 100 mM zinc ion, 100 mM cadmium ion, and 0.1 mM silver ion (Eccleston et al., 1985). The bacterium acquires the ability to grow even in the presence of 2 mM uranyl ion (Martin et al., 1983). Furthermore, it becomes resistant to arsenate and arse-nite by training a strain of the bacterium has been obtained which oxidizes ferrous ion in the presence of 80 mM arsenite and 287 mM arsenate (Collinet and Morin, 1990 Leduc and Ferroni, 1994). The resistant ability of the bacterium to arsenite and arsenate is important when they are applied for the solubilization of arsenopyrite (FeAsS) [reactions (5.8) and (5.9)]. Leptospirillum ferrooxidans is generally more sensitive to heavy metal ions than A. ferrooxidans (Eccleston et al., 1985). 

One final experiment addressed to the question of the egg box model and textural effects was to determine the ability of cadmium ions to reverse the effect of calcium ions on softening. Cadmium ion did not inhibit softening (Fig. 7) even though Kohn (29) has demonstrated that it binds to pectate with greater affinity than calcium. It also has an ionic radius nearly the same as calcium... 

Fig. 9. Evaluation of possible competition between calcium and cadmium ion for inhibition of cucumber mesocarp softening. From reference 47.

The first report on the use of ion-exchange columns with chemiluminescence detection was that by Buiguera et aI.[Sl] on the determination of zinc and cadmium through inhibition of the cobalt catalyzed chemiluminescence generation from luminol. The chloro-complexes of zinc and cadmium were retained by an anion exchanger and eluted separately using sodium hydroxide and nitric acid. Apparently, preconcentration effects were not pursued. 

It is known that cadmium ions in toxic concentrations significantly inhibited the growth and development of plants, also they have a negative impact on photosynthesis, respiration, water metabolism and mineral nutrition [19]. In our experiments the treatment of plants by bacilli increased the tolerance index of rye plants. The growth-stimulating effect of the bacteria, probably due to the fact that the bacilli can produce phytohormone-like substances [14, 15], and also increase the content of nutrients in the plant-available form [20] and inhibit the development of pathogenic microorganisms [14]. 

Cadmium inhibited rat brain s3maptosomal adenosine triphosphatase activity in vitro and was more potent in this respect than aluminum or manganese. All three metals reduced the uptake of choline, catecholamines, y-amino butyric acid, and glutamic acid by rat brain synaptosomes. Cadmium ions interfere with membrane function in rat brain synaptosomes by inhibiting the methylation of phospholipids. Cadmium has been found to be a much more potent inhibitor in this respect than aluminum or manganese. ... 

While direct interactions of cadmium ions with DNA appear to be of little importance, interactions with proteins are of high significance. Especially the DNA repair inhibitions but also altered cell proliferation and/or diminished cell cycle control have frequently been observed at low, non-cytotoxic concentrations of cadmium, raising the question of particularly sensitive targets of cadmium ions. Relevant mechanisms include elevated levels of ROS, interactions with homeostasis and cellular functions of essential metal ions like zinc, calcium, and iron and the interference with cellular redox regulation. 

Precipitation is often applied to the removal of most metals from wastewater including zinc, cadmium, chromium, copper, fluoride, lead, manganese, and mercury. Also, certain anionic species can be removed by precipitation, such as phosphate, sulfate, and fluoride. Note that in some cases, organic compounds may form organometallic complexes with metals, which could inhibit precipitation. Cyanide and other ions in the wastewater may also complex with metals, making treatment by precipitation less efficient. A cutaway view of a rapid sand filter that is most often used in a municipal treatment plant is illustrated in Figure 4. The design features of this filter have been relied upon for more than 60 years in municipal applications. 

The effect of perchlorate ions on cadmium electrodeposition was investigated in water-AN mixtures [227, 228]. The formation of ionic associates in the surface layer inhibited cadmium electrodeposition, and promoted the formation of higher quality coatings. 

In acidic solutions, the corrosion rate is relatively high. Studies on cadmium monocrystals and polycrystals in acidic chloride solutions revealed anodic dissolution independent of the crystallographic orientation the dissolution rate was controlled by the mass transport of CdCl" ions [331]. The inhibitive influence of adsorbed organic substances, for example, alcohols [332], phenotiazine [333], and some polymers (e.g. poly (vinyl alcohol), poly(acrylic acid), sodium polyacrylate. 

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