Micrograms Of Copper Research Articles

Disinfection of human enteric viruses in water by copper and silver in combination with low levels of chlorine

The efficacy of copper and silver ions, in combination with low levels of free chlorine (FC), was evaluated for the disinfection of hepatitis A virus (HAV), human rotavirus (HRV), human adenovirus, and poliovirus (PV) in water. HAV and HRV showed little inactivation in all conditions. PV showed more than a 4 log10 titer reduction in the presence of copper and silver combined with 0.5 mg of FC per liter or in the presence of 1 mg of FC per liter alone. Human adenovirus persisted longer than PV with the same treatments, although it persisted significantly less than HRV or HAV. The addition of 700 micrograms of copper and 70 micrograms of silver per liter did not enhance the inactivation rates after the exposure to 0.5 or 0.2 mg of FC per liter, although on some occasions it produced a level of inactivation similar to that induced by a higher dose of FC alone. Virus aggregates were observed in the presence of copper and silver ions, although not in the presence of FC alone. Our data indicate that the use of copper and silver ions in water systems may not provide a reliable alternative to high levels of FC for the disinfection of viral pathogens. Gene probe-based procedures were not adequate to monitor the presence of infectious HAV after disinfection. PV does not appear to be an adequate model viral strain to be used in disinfection studies. Bacteroides fragilis bacteriophages were consistently more resistant to disinfection than PV, suggesting that they would be more suitable indicators, although they survived significantly less than HAV or HRV.

Efficacy of copper and silver ions and reduced levels of free chlorine in inactivation of Legionella pneumophila.

Water disinfection systems utilizing electrolytically generated copper and silver ions (200 and 20, 400 and 40, or 800 and 80 micrograms/liter) and low levels of free chlorine (0.1 to 0.4 mg/liter) were evaluated at room (21 to 23 degrees C) and elevated (39 to 40 degrees C) temperatures in filtered well water (pH 7.3) for their efficacy in inactivating Legionella pneumophila (ATCC 33155). At room temperature, a contact time of at least 24 h was necessary for copper and silver (400 and 40 micrograms/liter) to achieve a 3-log10 reduction in bacterial numbers. As the copper and silver concentration increased to 800 and 80 micrograms/liter, the inactivation rate significantly (P less than or equal to 0.05) increased from K = 2.87 x 10(-3) to K = 7.50 x 10(-3) (log10 reduction per minute). In water systems with and without copper and silver (400 and 40 micrograms/liter), the inactivation rates significantly increased as the free chlorine concentration increased from 0.1 mg/liter (K = 0.397 log10 reduction per min) to 0.4 mg/liter (K = 1.047 log10 reduction per min). Compared to room temperature, no significant differences were observed when 0.2 mg of free chlorine per liter with and without 400 and 40 micrograms of copper and silver per liter was tested at 39 to 40 degrees C. All disinfection systems, regardless of temperature or free chlorine concentration, showed increase inactivation rates when 400 and 40 micrograms of copper and silver per liter was added; however, this trend was significant only at 0.4 mg of free chlorine per liter.

Upper Limits of Zinc, Copper and Manganese in Infant Formulas

Upper limits are proposed for zinc, copper and manganese in infant formulas. At these limits intakes would be lower than would intakes shown to be associated with toxicity, but the upper limits of an entirely safe range of intake remain uncertain. The proposed limits provide a considerable margin beyond normal nutritional requirements, and it is not recommended that formulas should typically contain these quantities. The proposed upper limits (per 100 kcal) are 1.5 mg of zinc, 200 micrograms of copper and 50 micrograms of manganese.

Excretion of laccase by sycamore (Acer pseudoplatanus L.) cells. Effects of a copper deficiency.

Copper-deprived sycamore (Acer pseudoplatanus) cells do not excrete molecules of active laccase in their culture medium. In the range of 2-100 micrograms of copper initially present per litre of nutrient solution, the total laccase activity measured in the cell suspensions at the end of the exponential phase of growth was closely proportional to the amount of added copper. However, copper-deprived cells excreted the laccase apoprotein (laccase without copper) at the same rate as copper-supplied cells excreted the active, copper-containing, laccase. When the culture medium was initially supplied with limiting amounts of copper, the active laccase was excreted until all copper molecules were metabolized. Thereafter, the laccase apoprotein was excreted. Consequently, at the end of the exponential phase of growth, the cell supernatants contained a mixture of apoprotein and copper-containing laccase. After purification and concentration, this mixture of copper-containing laccase (blue) and laccase apoprotein (slightly yellow) showed a yellow-green colour. Under copper-limiting culture conditions an equivalent decrease of Type 1, Type 2 and Type 3 Cu2+ was observed. Addition of copper to copper-deficient enzyme solutions does not result in a recovery of the enzyme activity. However, when added to copper-deficient sycamore-cell suspensions, copper induced a recovery of the excretion of active enzyme, at a normal rate, within about 10 h. The first molecules of active laccase were excreted after 3-4 h.

Antilupus activity of copper (II)

Collagen-like syndrome was induced in rats by oral hydralazine administration during 5 months. After 4 months, a subgroup of rats was shifted from the standard diet to the diet supplemented with copper (II) (60 micrograms of copper per g of pellet) as copper sulphate. A decreased serum copper concentration was noted, LE cells were observed in the blood of 75% of rats fed with standard diet. In the subgroup of copper supplemented rats, the LE cells were observed in 40% of rats only. The activity of superoxide dismutase, the antioxidative copper-dependent enzyme, was significantly lower in erythrocytes of rats fed with standard diet, than the activity in rats fed with copper supplemented diet. These results are briefly discussed.

Copper metabolism in mottled mouse mutants. The effect of copper therapy on lysyl oxidase activity in brindled (Mobr) mice.

Lysyl oxidase activity in extracts of skin from 1-day-old Mobr/Y mice was found to be between 50 and 60% of that in corresponding extracts from littermate +/Y mice of the same age. It was increased to 84-150% of that in the latter by prior treatment of the Mobr/Y mice at 7 days of age with a single subcutaneous injection of 50 micrograms of copper, retained as Cu+ in an alkyl polyether/sebacic acid solution. This suggests that in this form the copper is able to by-pass the block in copper metabolism and is deliverable to copper-requiring processes.

Copper metabolism in mottled mouse mutants: copper therapy of brindled (Mobr) mice.

Copper therapy was applied to brindled mouse mutants, which suffer from lethal hypocupraemia, by using cuprous and cupric solutions. The method of treatment was a single subcutaneous injection of 50 microgram of copper at 7 days of age. Early effects of the dose were: prevention of the tremors and spasms seen in untreated mutants, raising to normal and near-normal of caeruloplasmin oxidase and lysyl oxidase activities and pigmentation of skin and fur. Growth of mutants was retarded up to 23 days of age, but thereafter they rapidly gained weight to be nearly normal by 60 days of age. At 3 days after injection, copper concentrations in previously deficient mutant organs apart from liver were at least as much as those of treated normals, which had remained unchanged. Copper in mutant livers had increased only slightly in comparison with the normal control. A state of copper deficiency recurred in mutant tissues by 25 days after injection. A solution of Cu+, retained as such by an alkyl polyether, and sebacic acid resulted in greater growth rates after 23 days than did three other copper treatments. Cu+ may have resulted in an improved growth response owing to it being more readily metabolized than C12+. Delayed release of copper from the site of injection may have played an important role.

Copper and the Role of Isopods in Degradation of Organic Matter

On an artificial substrate of filter paper, Porcellio scaber cannot extract copper from leaf litter. If one increases the copper content of the food by soaking the leaves in solutions of CuSO(4) or in organic extracts, assimilation of copper becomes possible, but only at concentrations higher than 1 microgram of copper per milligram of ash. This is too high a level for primary vegetable matter to be considered a plausible source of copper for isopods. I present evidence that in fecal material the critical level at which assimilation of copper becomes feasible is lower than in primary organic material by nearly an order of magnitude, and that isopods are obliged to switch to coprophagy in order to allow accumulation of copper in their bodies.

THe analysis of beryllium and beryllium oxide—II: The determination of copper

A method is described for the determination of copper in beryllium or beryllium oxide by extraction of the neocuproïne complex with methyl isobutyl ketone. The method is accurate to ±5% or ±2.5 micrograms of copper, whichever is greater. The accuracy and sensitivity could be improved by appropriate choice of sample size, volume of extract and/or cell length. Of the 68 elements investigated, only gold interferes in 10 mg amounts; in this case a slight loss of copper is caused by occlusion or co-precipitation.

Small Amounts of Copper in Dyes and Rubber Chemicals. Colorimetric Determination with Zinc Dibenzyldithiocarbamate

Abstract This work was undertaken to provide a more specific method for the routine determination of small amounts of copper in rubber chemicals, dyes, and dyed fabrics. A dithiocarbamate type of reagent—a 0.01 per cent solution of zinc dibenzyldithiocarbamate in carbon tetrachloride—will selectively extract copper from acid solutions containing relatively large amounts of most other metals. The method is accurate and reproducible to about 0.5 microgram in the range of 0.5 to 40 micrograms of copper. No precipitations or filtrations are required. The reagent is commercially available, the reagent solution and the color of the extracted copper dibenzyldithiocarbamate are stable, and the acid solution remaining after extraction may be used to determine other metals. Because copper dibenzyldithiocarbamate is selectively extracted from solutions containing relatively large amounts of many other metallic ions, the reagent may be used to determine small amounts of copper in metals and their salts.

Estimation of Tenths of Microgram of Copper

Estimation of Tenths of Microgram of Copper

The Quantitative Spectrochemical Determination of Barium, Strontium, and Calcium*

The procedure herein described was developed for the determination of barium, strontium, and calcium in mixtures of the carbonates of these metals in which they are present in the respective ratios of approximately 10:10:1. While the procedure is primarily designed for samples ranging in weight between 50 and 200 micrograms, it is also applicable to samples of greater weight by diluting solutions thereof to proper working concentration. Samples are dissolved in dilute hydrochloric-acetic acid; 500 micrograms of copper (as nitrate solution) is added to each, and the solutions diluted to 1.0-ml volume. Aliquots of these solutions and of a graduated series of standards, similarly prepared, are pipetted to water-proofed graphite electrodes, dried, and excited in the alternating current arc. The resulting spectra are recorded on the same plate, and the determinations are made by the usual internal-standard technique.

TOXIC EFFECTS OF COPPER ON ATTACHMENT AND GROWTH OF BUGULA NERITINA

Copper paint surfaces prevent the establishment of Bugula neritina (1) by repelling or killing the larvae and (2) by inhibiting growth and metamorphosis of attached larvae.Copper paints with leaching rates less than 10 micrograms of copper per square centimeter per day permit the larvae to attach in large numbers and to grow and differentiate. Paints with leaching rates greater than 15 micrograms per square centimeter per day allow only a small percentage of larvae to attach and completely inhibit their growth. Large percentages of larvae occasionally attach. to paint surfaces with leaching rates between 10 and 15 micrograms per square centimeter per day, but these do not develop colonies.No consistent effect of slime film on larval attachment was noted. Its presence is not prerequisite to attachment.Precise relationships between copper concentration and growth of Bugula ancestrulae are demonstrated. Growth in sea-water solutions of copper is inversely proportional to the concentration up to 0.3 mg. per l...

STUDIES ON BIOLOGICAL OXIDATIONS: V. COPPER AND HEMOCHROMOGENS AS CATALYSTS FOR THE OXIDATION OF ASCORBIC ACID. THE MECHANISM OF THE OXIDATION

SUMMARY Ascorbic acid is not autoxidizable in acid and neutral solutions up to pH 7.0. It is autoxidizable in alkaline solutions, the rate of autoxidation increasing considerably as the pH increases. Among the metallic salts tested (Mn, Ni, Fe, Co, Ca, Cu) copper is the only catalyst for the oxidation of ascorbic acid, its catalytic action being noticed in concentrations as small as 46 micrograms of copper per liter. This catalytic effect is completely inhibited by 0.001 M KCN, and to the extent of 80 per cent by mixtures of CO : 02 of 95 : 5. When this oxidation is performed in acid and neutral solutions, there is an uptake of oxygen of 1 atom per molecule of the substrate. The oxidized form can be completely reduced by H&S up to pH 5.0. Above this pH the amount of ascorbic acid recovered gradually decreases until at pH 7.6 only 4 per cent of the oxidized form can be recovered as ascorbic acid. Hydrogen in the presence of colloidal palladium does not reduce oxidized ascorbic acid. The temperature coefficient for the oxidation of ascorbic acid by oxygen with copper as catalyst is 1.65. Electromotively active oxidation-reduction systems of suitable potential can also act as oxidizing catalysts. The hemochromo- gens of nicotine, pyridine, and pilocarpine, taken as representative examples, were found to act as catalysts. The mechanism of the oxidation of ascorbic acid by atmospheric oxygen in the presence of catalysts has been discussed. After this paper was sent in for publication there came to the authors’ attention two recently published communications bearing a relation to our experiments. Mawson (25) and Kellie and Zilva (26) have reported on the stability of ascorbic acid in the absence of catalysts, and on the catalytic power of copper. Kellie and Zilva report also that “the oxidation catalysed by Cu was very much slower when NaCl (0.1 M) was present.” We found no such inhibiting effect in our experiments. In fact, 0.02 mM of ascorbic acid in phosphate buffer + 0.1 M NaCl, with 0.0002 mM of CuCh as catalyst (final pH, 6.00), was half oxidized in 16.2 minutes. In Table II it can be seen that at the same pH value, without NaCl, ascorbic acid was half oxidized in 15 minutes. On the other hand, the addition of amino acids, through the