Addition Of CuSO Research Articles

The catalytic effects of copper ions on photo-oxidation in TiO 2 suspensions: The role of superoxide radicals

UV photolysis of aerated aqueous suspensions of TiO 2 (Degussa P25) containing CH 3OH at pH 8.5 produces HCHO. Addition of CuSO 4 affects the rate of HCHO formation ( R HCHO) in two opposite ways. Below 2 μM, R HCHO increases with increasing [CuSO 4] while at higher concentrations it slows down. The enhancement of R HCHO at very low [CuSO 4] is attributed to catalytic dismutation of O 2 − forming H 2O 2 and O 2. At higher [CuSO 4], R HCHO decrease is attributed to removal of mobile holes by copper. Square root dependency of HCHO yield on the absorbed light density is observed in the entire [CuSO 4] range used. The square root dependency is generally attributed to competition between second-order electron–hole recombination and first-order trapping, although the lifetime of both electrons and holes is too short to enable their accumulation in the same nano-volume. It is shown here that the electron–hole recombination path involves reaction of the mobile holes with adsorbed O 2 −. The experimental results provide indirect evidence that adsorbed O 2 − radical ions, which are produced via O 2 reaction with the TiO 2 electrons, are important for the well known square root dependency. Unlike the mobile and trapped electrons, O 2 − has a relatively long lifetime and its accumulation in the nano-volume upon successive absorptions of photons is feasible. It is concluded that the reaction between the accumulated O 2 − and mobile holes is responsible for the square root law. The decrease of K d, which has been suggested as a standard parameter for the nature of TiO 2 by added Cu(II) implies an apparent improvement of the TiO 2 quality as a photocatalyst.

Screening of agro-industrial wastes to produce ligninolytic enzymes by Phanerochaete chrysosporium

Ligninolytic enzyme production by solid-state cultures of Phanerochaete chrysosporium BKM-F-1767 was investigated by employing different agro-industrial wastes, such as fishery residues, brewery waste, apple waste (pomace) and pulp and paper industry sludge. Different enzyme inducers, such as veratryl alcohol, Tween-80 and CuSO 4 at concentrations of 2 mM, 0.5% (v/w) and 3 mmole/kg, respectively were also tested. Use of veratryl alcohol and Tween-80 resulted in maximum manganese peroxidase (MnP) activity of 17.36 ± 0.5, 540.2 ± 5.1, 631.25 ± 14, and 507.5 ± 26.87 U/gds (units/gram dry substrate), respectively, for different wastes. Maximum lignin peroxidase (LiP) activity of 141.38 ± 3.39 and 14.1 ± 0.5 U/gds was attained with pomace and pulp and paper, respectively. Laccase activities were found to be insignificant for all wastes. Addition of Tween-80 and CuSO 4 resulted in highest values of MnP activity of 17.4 ± 0.6, 291 ± 2.8, 213.5 ± 3, and 213.2 ± 3.2 U/gds for fishery waste, brewery waste, pomace and pulp and paper industry sludge, respectively. Addition of CuSO 4 to the culture medium enhanced laccase activity. Maximum laccase activities of 738.97 ± 9.2, 719.97 ± 14.6, 308.8 ± 12.1, and 94.44 ± 1.2 U/gds were obtained for brewery waste, pomace, pulp and paper industry sludge and fishery waste, respectively. Brewery wastes and pomace served as excellent sources for the production of MnP, LiP and laccases.

Plasma PAF-acetylhydrolase activity, inflammatory markers and susceptibility of LDL to in vitro oxidation in patients with type 1 diabetes mellitus

Aims We evaluated if type 1 diabetic patients have altered levels of low-grade inflammatory markers including platelet-activating factor acetylhydrolase (PAF-AH) activity, high-sensitivity C-reactive protein (hs-CRP), white blood cells count (WBC), erythrocyte sedimentation rate (ESR) and LDL-cholesterol oxidation coefficient (OxC), and whether their levels are related to clinical complications and the metabolic profile. Methods We studied cross-sectionally 118 outpatients with type 1 diabetes both with ( n = 38) and without ( n = 80) clinical chronic complications, and 110 controls subjects. Results Diabetic patients had higher levels of PAF-AH activity ( p = 0.02), hs-CRP ( p = 0.001), WBC ( p = 0.004) and ESR ( p = 0.0001) than controls. Patients with type 1 diabetes had earlier OxC than the non-diabetic subjects at 1 and 3 h ( p = 0.01) after the addition of CuSO 4. No difference was noted between patients with and without chronic complications. In the patients, correlations were found between PAF-AH activity and OxC at 1 and 3 h. Conclusions It was concluded that the susceptibility of LDL to in vitro oxidation and low-grade inflammation are increased in patients with type 1 diabetes and related to each other. The presence of these markers is probably independent of the presence of chronic clinical complications and reveals the development of early pro-inflammatory state.

A New Stenotrophomonas maltophilia Strain Producing Laccase. Use in Decolorization of Synthetics Dyes

Laccase activity was detected in a soil bacterium Stenotrophomonas maltophilia AAP56 identified by biochemical and molecular methods. It was produced in cells at the stationary growth phase in Luria Bertani (LB) medium added by 0.4 mM copper sulfate. The addition of CuSO(4) in culture medium improved production of laccase activity. However, one laccase enzyme was detected by native polyacrylamide gel electrophoresis. The enzyme showed syringaldazine (K (m) = 53 microM), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (K (m) = 700 microM), and pyrocatechol (K (m) = 25 microM) oxidase activity and was activated by addition of 0.1% (v/v) Triton-X-100 in the reaction mixture. Moreover, the laccase activity was increased 2.6-fold by the addition of 10 mM copper sulfate; the enzyme was totally inhibited by ethylenediaminetetraacetic acid (5 mM), suggesting that this laccase is a metal-dependant one. Decolorization activity of some synthetic dyes (methylene blue, methyl green, toluidine blue, Congo red, methyl orange, and pink) and the industrial effluent (SITEX Black) was achieved by the bacteria S. maltophilia AAP56 in the LB growth medium under shaking conditions.

Effects of Cu 2+-exchanged montmorillonite on growth performance, microbial ecology and intestinal morphology of Nile tilapia ( Oreochromis niloticus)

A total of 360 Nile tilapia at an average initial body weight of 3.9 g were randomly allocated to 4 treatments, each of which had three replicates of 30 fish/tank and used to investigate the effects of Cu 2+-exchanged montmorillonite (Cu-MMT) on growth performance, microbial ecology of the skin, gill and intestine, and intestinal morphology. The dietary treatments were: 1) basal diet, 2) basal diet + 1.5 g/kg MMT, 3) basal diet + 30 mg/kg copper as CuSO 4 (equivalent to the copper in the Cu-MMT treatment group), or 4) basal diet + 1.5 g/kg Cu-MMT. The results showed that supplementation with Cu-MMT significantly improved growth performance as compared to control and fish fed with Cu-MMT had higher growth performance than those fed with MMT or CuSO 4. Supplementation with Cu-MMT reduced ( P < 0.05) the total intestinal aerobic bacterial counts and affected the composition of intestinal microflora with a tendency of Aeromonas, Vibrio, Pseudomonas, Flavobacterium, Acinetobacter, Alcaligence, Enterobacteriaceae decreasing as compared with control. Measurements of villus and microvillus heights at different sites of the intestinal mucosa indicated that dietary addition of MMT or Cu-MMT improved intestinal mucosal morphology. However, the microbial ecology of the skin and gill was not affected by the addition of CuSO 4, MMT or Cu-MMT. Supplementation with CuSO 4 had no ( P > 0.05) effect on the growth performance, microbial ecology and intestinal morphology. The results showed that Cu-MMT exhibited antibacterial activity in vivo and protected intestinal mucosa from invasion of pathogenic bacterium and toxins, resulting in a positive effect on the growth performance.

Characterization of aspartate transcarbamylase activity from gonads of the soft shell clam, Mya arenaria

Aspartate transcarbamylase (ATCase, EC 2.1.3.2) has been shown to be a good index of the reproductive cycle in marine molluscs. However, this enzyme has never been studied in the soft shell clam Mya arenaria. The characteristics of gonadal ATCase of the soft shell clam, Mya arenaria were therefore determined since we need powerful tools to assess the degree of effects of endocrine disruptors in this species at risk. Enzyme kinetic values observed at pH 8.3 were significantly lower than those measured at pH 9.4. The optimal conditions for the enzyme assays were reached in the presence of a 10 mM of substrate concentration and at pH 9.2 for 60 min at 37 °C. We have found that the enzyme was heat sensitive, markedly activated by DMSO and DMF, but no effect was observed with ethanol, ATP or CTP. However, clam ATCase activity was partly inhibited by the addition of CuSO 4 and PHMB to the medium, an inhibition that could be attributed to the presence of SH sites in cysteine residues localized in the catalytic site of this enzyme. All these results will be very useful in the near future to study the gametogenetic process of Mya arenaria, since little is known about the factors that control the physiological process of reproduction in this bivalve of ecological and economic importance. Studies of variations of the activity of aspartate transcarbamylase will also be useful as a potential biomarker to evaluate the disruption of gametogenesis in clams exposed to endocrine disruptors in situ.

Inhibition of proteases during fermentation improves xylanase production by alkali tolerant Aspergillus fumigatus ARl

An alkali-tolerant Aspergillus fumigatus ARl produced a high level of xylanase (228 U/ml) at 42 h of submerged fermentation at pH 9.0. During later culture periods, xylanase activity declined considerably and reached 45 U/ml at 90 h. This trend is because of proteolytic degradation of xylanases since A. fumigatus co-produced multiple proteases with high activity (120–159 U/ml) during submerged fermentation. Xylanase and protease were found to be active over a wide range of pH from 5.5 to 9.0. In contrast, protease lost its activity completely in the presence of CuSO 4 (25 mM) while xylanase remained active. The selective inhibition of proteases by the addition of CuSO 4 to the culture medium prevented proteolytic degradation of xylanase and improved the production of xylanase by 3-fold.

The use of electrochemical measurements in the flotation of a platinum group minerals (PGM) bearing ore

Electrochemical potential is considered an important parameter for controlling the recovery and selectivity of sulphide minerals during flotation. The aim of this work was to use mineral potential measurements to gain an understanding of respective mineral flotation performance in the processing of a platinum group mineral (PGM) bearing ore, whilst manipulating the chemical conditions in the pulp. Sulphide mineral potentials were logged during the conditioning stage of the flotation tests. Varying the milling environment and conditioning pH affected the chemical conditions in the pulp. At any condition the mixed potential of the mineral electrodes varied, spanning a range of approximately 100 mV, and increased as follows: pyrrhotite, pentlandite, chalcopyrite, pyrite and platinum. The addition of CuSO 4 caused the potential to increase, whilst the addition of xanthate caused to the potential to decrease. The magnitude of the changes in potential for the various mineral electrodes on reagent addition was not the same and followed the recovery trend of the minerals viz. chalcopyrite>pentlandite>pyrrhotite. Chalcopyrite recovery was unaffected by differences in milling media and conditioning. Pyrrhotite flotation was inhibited when the ore was milled in the plant circuit even though the mixed potentials were similar to those measured in laboratory milled pulps. This was presumably due to excessive oxidation in the grinding and classification circuits of the plant. Acid conditioning improved the recovery of pyrrhotite through cleaning the mineral surface from hydrophilic iron oxy/sulphoxy species and also showed an enhanced reaction with xanthate. Pyrrhotite flotation was only slightly inhibited when its mixed potential was below the equilibrium potential for dixanthogen formation.

Development of enzymatic assays for quantification of intracellular lamivudine and carbovir triphosphate levels in peripheral blood mononuclear cells from human immunodeficiency virus-infected patients.

In this paper, we describe the development and use of enzymatic assays to determine intracellular lamivudine triphosphate (3TCTP) and carbovir triphosphate (CBVTP) concentrations in peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus (HIV)-infected patients. The assays involve inhibition of HIV reverse transcriptase (RT), which normally incorporates radiolabeled deoxynucleoside triphosphates into a synthetic template primer. For the 3TCTP assay, a preincubation procedure was added whereby 3TCTP becomes incorporated before [(3)H]dCTP. At a 1:400 template primer dilution, control product formation was reduced by 88.0% with 0.8 pmol of 3TCTP. Standard 3TCTP inhibition curves were performed using this procedure. For the CBVTP assay, 0.1 pmol of CBVTP inhibited control product formation with and without the use of a preincubation step, so inhibition curves were constructed using both procedures. However, reduced template primer stability with assays using preincubation steps led to a single-incubation procedure being adopted for future studies. The presence of PBMC extracts interfered with the 3TCTP assay. However, this was overcome by the addition of CuSO(4). PBMC extracts did not interfere with the CBVTP assay. Intracellular 3TCTP and CBVTP concentrations were determined in PBMCs from HIV-infected patients over 24 h or greater. Peak concentrations were obtained 6 to 8 h after dosing, and the half-lives of the anabolites suggested the possibility of once-daily dosing. These assays are currently being used for determination of 3TCTP and CBVTP concentrations in clinical studies.

Oxidation of low-density lipoprotein in normotensive type 2 diabetic patients. Comparative effects of enalapril versus nifedipine: a randomized cross-over over study

The role of lipoprotein oxidation in promoting atherosclerosis is gaining recognition as its spectrum of effects is being unveiled. Accelerated atherosclerosis is a major cause of morbidity and mortality in diabetic patients. Treatment with ACE inhibitors reduces oxidation of low-density lipoprotein (LDL-ox) in hypertensive subjects, however, their effect on LDL-ox in diabetic patients is yet obscure. To evaluate the effect of the ACE inhibitor enalapril and the calcium channel blocker nifedipine on LDL oxidation in normotensive type 2 diabetic patients. A randomized single blinded cross-over study was conducted on 24 nonobese, metabolically stable, normotensive patients with type 2 diabetes who were randomly allocated to receive either enalapril, 10 mg/day, or nifedipine, 30 mg/day, for 4 weeks followed by a 2-week washout period. They were then crossed over to a 4-week course with the alternate drug. The oxidation of LDL was evaluated by three methods: dialdehyde analysis using the thiobarbituric acid reactive substances assay with and without the addition of CuSO 4 as well as determination of conjugated dienes in the LDL lipid extract. The propensity of the serum to oxidize LDL was reduced by enalapril by 17–28% depending on the laboratory method used ( P=0.0001). Treatment with nifedipine resulted in a rise in LDL-ox of 7–11% as compared to baseline ( P<0.05). The difference between the effects of enalapril and nifedipine was statistically significant with all three laboratory methods used ( P=0.0001). Both drugs were equally effective in reducing systolic and diastolic blood pressure without affecting HbA 1c levels and lipid profile. The albumin excretion rate was significantly reduced during treatment with enalapril returning to baseline levels during the washout period and the nifedipine treatment course. Our findings suggest that oxidation of LDL is attenuated by ACE inhibition and augmented by some calcium channel blockers. This observation may contribute insight into the underlying mechanism of the therapeutic effects of ACE inhibition in diabetic patients.

Responses of rat cuproenzymes to variable dietary copper

Weanling, 19-day-old, male Sprague-Dawley rats were offered a basal diet low in copper (Cu), 0.40 mg/kg (6.3 nmol/g), and drinking water containing 0, 0.5, 1, or 10 (Cu-adequate) mg Cu/L. After 30 days, plasma and heart cuproenzymes were assayed. Body weight and hemoglobin were equivalent among groups. Rats drinking I mg Cu/L did not have elevated heart/body weight, lower liver Cu, or higher liver Fe compared with Cu-adequate rats. However, activity of two blood enzymes (plasma ceruloplasmin and serum peptidylglycine α-amidating monooxygenase (PAM)) and three heart enzymes (cytochrome c oxidase, Cu, Zn-superoxide dismutase, and PAM) were lower compared with rats supplemented with 10 mg Cu/L. Groups drinking 0.5 mg Cu/L or deionized water had even lower activities including that of heart dopamine-β-monooxygenase. Serum and heart PAM activities patterned one another, suggesting that serum PAM may be a suitable marker of tissue Cu status. Addition of CuSO 4 to the PAM assay increased the apparent activity in a manner inversely related to dietary Cu intake in both heart and serum samples. The Cu stimulation index (activity with added Cu/activity with basal Cu) may also be a useful tool to assess Cu status.

Metal ionic induction: Expression of monoamine oxidase gene of Escherichia coli is induced by copper ion

The effect of copper concentration of the culture medium on the production of copper-containing monoamine oxidase by Escherichia coli K-12 was studied. As previously reported, the addition of CuSO 4 to the culture medium resulted in an increase in the total enzymatic activity. The added copper had been thought to enhance the activity of amine oxidases by affecting protein conformation. However, western blot analysis reveals that the addition of CuSO 4 also results in an increase in the monoamine oxidase content of E. coli cells. Furthermore, northern blot analysis results indicate that an increase in monoamine oxidase activity also occurs at the transcriptional level. Increased transcription was observed in accordance with the addition of CuSO 4 up to 50 μM final concentration.

Poly(β-malic acid) production by the non-growing cells of Aureobasidium sp. strain A-91

Poly( l-malic acid), PM, production by the non-growing cells of Aureobasidium sp. strain A-91 was investigated. Reaction conditions were optimized using non-growing cells of strain A-91. The addition of CuSO 4 to the cell preparation medium was found to be effective to prepare active cells for PM production. The non-growing cells of the strain yielded 80.0 g/ l PM during 5 days' incubation at 30°C under optimal conditions (160 g/ l glucose and 40 g/ l CaCO 3).

Modification of the electrodeposition method of molybdenum black coatings for solar energy applications

Addition of CuSO 4 to the molybdenum black plating bath gave a selectivity factor value α/ε of 3.6, when α = 0.87. It was observed that the properties of these coatings depend on the deposition conditions and bath composition. Coatings of higher selectivity factor (α/ε = 5, when α = 0.87) could be obtained by using an intermediate layer of bright nickel instead of dull nickel. The microstructure of the electrodeposited coatings consists of relatively flat, smooth, irregular platelets with prominent fissures. The coatings have irregularly shaped particles on the surface and consist mainly of molybdenum oxide.

Exogenously added copper does not increase the production of copper amine oxidase in lentil seedlings

The effect of copper ions, the inorganic cofactor of amine oxidase (AO; EC 1.4.3.6), on the production of this enzyme in lentil ( Lens culinaris) seedlings was studied. The addition of CuSO 4 to the imbibition water during the germination of lentils increased the AO activity. However, the amounts of specific mRNA and protein were not affected by the presence of Cu 2+. Furthermore, the addition of Cu 2+ to homogenates of lentil seedlings grown in the absence of the metal substantially increased the AO activity. Therefore, it appears that exogenously added Cu 2+ does not increase the production of AO in lentil seedlings which are still able to synthesize the copper-free enzyme. The addition of Cu 2+ seems to reconstitute the enzymatically active holoprotein.

Gold recovery from carbon-in-pulp eluates by precipitation with a mineral acid II. Gold bullion production from precipitate, treatment of barren solution, the settling rate of precipitate and assisting precipitation by addition of CuSO 4·H 2O in a recalcitrant eluate

This paper is the second in a series of three to describe a process for gold recovery from carbon-in-pulp (CIP) eluates, containing gold but contaminated with base metals. Recovery of virtually all the gold is effected by either hydrochloric or sulphuric acidification of the eluate. In a previous paper the effect of pH and temperature on the precipitation step were described. An attempt was also made to elucidate the chemical nature of the precipitate using X-ray techniques. In this paper, the production of gold bullion from precipitate is described. Treatment of barren solution from the precipitation step to recover residual gold values, the settling rate of the precipitate and precipitation of the gold from a recalcitrant eluate, low in base metals, by the addition of CuSO 4·5H 2O are discussed. In a final paper, a material balance will be proposed for a batch plant to produce a nominal 100 kg of gold from real plant eluate using the precipitation route. Precipitation will then be compared with electrowinning where it is shown to have certain advantages for specific eluates.

Gold recovery from carbon-in-pulp eluates by precipitation with a mineral acid I. Precipitation of gold in eluates contaminated with base metals

This paper is the first in a series of three to describe a process for gold recovery from carbon-in-pulp (CIP) eluates, containing gold but contaminated with base metals. Recovery of virtually all the gold is effected by either hydrochloric or sulphuric acidification of the eluate. In this paper the effect of pH and temperature on the gold precipitation step is described. An attempt is also made to elucidate the chemical nature of the precipitate using X-ray techniques. In a second paper, the production of gold bullion from the precipitate is described. Treatment of barren solution from the precipitation step to recover residual gold values, the settling rate of the precipitate and precipitation of the gold from a recalcitrant eluate, low in base metals by the addition of CuSO 4·5H 2O will also be discussed. In a final paper, a material balance is proposed for a batch plant to produce a nominal 100 kg of gold from real plant eluate using the precipitation route. Precipitation is compared with electrowinning where it is shown to have certain advantages for specific eluates.

Gold recovery from carbon-in-pulp eluates by precipitation with a mineral acid III. The acid precipitation step in applications

This paper is the third in a series of three to describe a process for gold recovery from carbon-in-pulp (CIP) eluates, containing gold but contaminated with base metals. Recovery of virtually all the gold is effected by either hydrochloric or sulphuric acidification of the eluate. In the first paper, the effects of pH and temperature on the precipitation step were described. An attempt was also made to elucidate the chemical nature of the precipitate using X-ray techniques. In the second paper, the production of gold bullion from precipitate was described. Treatment of barren solution from the precipitation step to recover residual gold values, the settling rate of the precipitate and precipitation of the gold from recalcitrant eluates, low in base metals, by the addition of CuSO 4·5H 2O were also discussed. In this paper, a material balance is proposed for a batch plant to produce a nominal 100 kg of gold from real plant eluate using the precipitation route. Precipitation is also compared with electrowinning and is shown to have certain advantages for specific eluates.

Flotation of sulphide minerals by anionic and cationic dyes

Some dyes such as eriochrome blue black B, eriochrome black T, barium diphenylamine sulfonate, fluorescein acid, bromophenol blue, safranine T, crystal violet and methylene blue are able to float galena and sphalerite either without or with CuSO 4. Some of these dyes could perhaps be used for selective separation of these sulphide minerals from a complex ore since the addition of CuSO 4 improves the flotation of sphalerite as well as it depresses galena. The sulphide/potassium ethyl xanthate system does not show this advantage. Pyrite can be floated with fluorescein acid under oxidizing conditions.

Cerulein mRNA and peptide α-amidation activity in the skin of Xenopus laevis: Stimulation by norepinephrine

The skin of Xenopus laevis, because of its high concentrations of amidated peptides, is an excellent model for the study of neuropeptide biosynthesis. In this paper we determined levels of the mRNAs which encode cerulin and characterized the enzymatic activity which likely produces the carboxyl terminal α-amide moiety of cerulein. This enzyme is stimulated by the addition of CuSO 4 and ascorbate and requires the presence of molecular oxygen and is thus similar to the peptidyl-glycine α-amidating monooxygenase (PAM) described in mammals. Hybridization analysis showed that three cerulein mRNAs of different molecular sizes are present in varying proportions in the skin of individual frogs. Injection of norepinephrine into the dorsal lymph sac of Xenopus caused immediate secretion and depletion from skin of PAM activity but did not cause a comparable immediate decrease in skin levels of cerulein mRNA or total RNA. By 2 weeks after norepinephrine injection, cerulein mRNA levels increased to fourfold over control levels. By 4 weeks, skin PAM activity was almost restored to control levels.