Effect Of Cystine Research Articles

Effect of Cystine in Alkaline CMP Slurry on Controlling the Galvanic Corrosion at Al-Co Interface

As the feature size of integrated circuit (IC) shrinks down to 28 nm and below, aluminum (Al) is considered to be one of the suitable gate materials, and cobalt (Co) is considered to be one of the suitable barrier materials. During chemical mechanical polishing (CMP) of the Al-Co gate, galvanic corrosion occurs when Al and Co with large open-circuit potential (Eocp) difference contact each other in device structure and are exposed to conductive CMP slurry. In this paper, the adsorptive properties of the complex products formed by cystine and metal Al and Co were investigated. By means of potentiometric dynamic and static polarization measurements, impedance monitoring technology and adsorption model establishment, the complex products were adsorbed on the surface of Al and Co in physical and chemical form, which hindered the corrosion of Al and Co and achieved the goal of reducing their galvanic corrosion. The dynamic potential difference between Al and Co was reduced to 23 mV, and the static Ecorr difference was reduced to 30 mV with cystine concentration of 8 mM/L. The dynamic corrosion current (Icorr) difference was 2.936 μA/cm2, and the static Icorr difference was 0.835 μA/cm2.

Development of a Cost Effective Medium for Enhanced Production of Bacillus thuringiensis ?-endotoxin

The present study was carried out to develop a sustainable production medium using locally available cheap raw materials for biopesticide production by Bacillus thuringiensis subsp. kurstaki (Btk) HD-73. In submerged fermentation (SmF) condition, the conventional Luria-Bertani (LB) medium which was enriched with nitrogen source (10% defatted soybean meal) supported 28.57% sporulation and 125% endotoxin increase over LB (alone). The effect of cystine on sporulation and endotoxin synthesis was highly pronounced in LB-soybean medium (LBS) with a range of 19.54% and 131.35% higher endotoxin yield respectively in SmF condition. While basal salts supplemented in soybean-cystine (SMc) medium, it resulted in 7.65% endotoxin yield compared to LB-soybean-cystine (LBSc) medium. Addition of molasses balanced the C: N ratio in the SMc medium thus helping 84.85% higher endotoxin synthesis after 24 hours fermentation. Substitution of basal salts with cost effective sea water yielded about 19.27% less endotoxin. The optimum medium thus obtained consisting of soybean extract-molasses-cystine with sea water was used in 3.0 L bioreactor cultivation for endotoxin synthesis by Btk HD-73 under 30% saturation of dO2 through cascade of agitation and aeration. The production rate obtained was 1.67 fold higher in bioreactor than in shake flask culture.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 1-6

English

The present study was aimed at designing a cost effective medium for increasing the δ-endotoxin (Cry protein) synthesis by Bacillus thuringiensis (Bt) kurstaki HD-73 and indigenous Bt JSc1 harboring potential cry genes active against Lepidoptera insect orders. In this regard, locally available cheap molasses as carbon source, soybean extract as nitrogen source, sea water as trace elements source, cystine as sporulation/growth factor were considered to design a cost effective medium. Molasses and soybean extract in place of glucose and peptone in glucose-peptone (GP) medium supported 78.85% increase in δ-endotoxin synthesis in shake flask culture. The effect of cystine on endotoxin synthesis was highly pronounced in two media with a range of 80.32 to 110% higher δ-endotoxin under comparable fermentation conditions. While, substituting basal salts with sea water, Btk HD-73 yielded satisfactory and comparable endotoxin (74.3% of yield with basal salts). It was detected that the rapid decrease of endotoxin synthesis in the culture after 24 h was due to the degradation by the endogenous protease, synthesized with the progress of fermentation. This degradation of the endotoxin was much better protected (1.23 mg/ml endotoxin versus 0.312 mg/ml) by adding 4% ammonium sulfate in the optimized medium. The medium thus formulated with molasses, soybean extract, ammonium sulfate, cystine and sea water was then used in 3.0 L bioreactor cultivation for endotoxin synthesis by both Btk HD-73 and Bt JSc1 under 30% saturation of dO 2 through cascade control of agitation and aeration producing a higher yield of δ-endotoxin (2.1 and 2.63 mg/ml, respectively). The present results may successfully be used for large scale production of Bt biopesticide in Bangladesh. Keywords: Bacillus thuringiensis biopesticide, cheap substrates, cystine, protease activity, ammonium sulfate.

Inhibitive action of Cystine on the corrosion of low alloy steel ASTM A213 grade T22 in sulfamic acid solutions

The effect of Cystine on the corrosion behavior of low alloy steel ASTM A213 grade T22 in 0.5M sulfamic acid solutions have been investigated by various electrochemical techniques. The study was performed using electrochemical impedance spectroscopy (EIS) and the recent technique electrochemical frequency modulation (EFM). The results of the investigation show that the inhibition efficiency increased with increasing inhibitor concentration, but decreased with increasing the solution temperature and stirring velocity. All the collected results from the two techniques are in good agreements, which confirm the ability of EFM technique for monitoring the corrosion inhibition under the studied conditions.

Cysteamine prevents inhibition of adenylate kinase caused by cystine in rat brain cortex

Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in the lysosomes of almost all tissues. Although tissue damage might depend on cystine accumulation, the mechanisms of tissue damage are still obscures. Adenylate kinase, along with creatine kinase, is responsible for the enzymatic phosphotransfer network, crucial for energy homeostasis. Taking into account that cystine is known to inhibit creatine kinase activity, the two enzymes have thiol groups, and the strong interaction between the two activities, our main objective was to investigate the effect of cystine on adenylate kinase activity in the brain cortex of Wistar rats. For the in vivo studies, the animals were injected twice a day with 1.6 micromol/g body weight of cystine dimethylester and/or 0.46 micromol/g body weight of cysteamine from the 25th to the 29th postpartum day and sacrificed after 12 h. Cystine inhibited the enzyme activity in vitro in a concentration dependent way, whereas cysteamine prevented the inhibition. Adenylate kinase activity was found diminished in the brain cortex of rats loaded with cystine dimethylester and co-administration of cysteamine prevented the diminution of the enzyme activity. Considering that adenylate kinase together with creatine kinase is crucial for energy homeostasis, the release of cystine from lysosomes with consequent enzymes inhibition could impair energy homeostasis, contributing to tissue damage in patients with cystinosis.

Effect of Cystine on the Semiconductive and Protective Properties of Oxide Film Formed on Steel in sat. Ca(OH)2

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Cysteamine prevents and reverses the inhibition of creatine kinase activity caused by cystine in rat brain cortex

Cystinosis is a disorder associated with lysosomal cystine accumulation caused by defective cystine efflux. Cystine accumulation provokes a variable degree of symptoms depending on the involved tissues. Adult patients may present brain cortical atrophy. However, the mechanisms by which cystine is toxic to the tissues are not fully understood. Considering that brain damage may be developed by energy deficiency, creatine kinase is a thiolic enzyme crucial for energy homeostasis, and disulfides like cystine may alter thiolic enzymes by thiol/disulfide exchange, the main objective of the present study was to investigate the effect of cystine on creatine kinase activity in total homogenate, cytosolic and mitochondrial fractions of the brain cortex from 21-day-old Wistar rats. We performed kinetic studies and investigated the effects of GSH, a biologically occurring thiol group protector, and cysteamine, the drug used for cystinosis treatment, to better understand the effect of cystine on creatine kinase activity. Results showed that cystine inhibited the enzyme activity non-competitively in a dose- and time-dependent way. GSH partially prevented and reversed CK inhibition caused by cystine and cysteamine fully prevented and reversed this inhibition, suggesting that cystine inhibits creatine kinase activity by interaction with the sulfhydryl groups of the enzyme. Considering that creatine kinase is a crucial enzyme for brain cortex energy homeostasis, these results provide a possible mechanism for cystine toxicity and also a new possible beneficial effect for the use of cysteamine in cystinotic patients.

Regulation of type I collagen mRNA in lung fibroblasts by cystine availability.

The steady-state level of alpha1(I) collagen mRNA is regulated by amino acid availability in human lung fibroblasts. Depletion of amino acids decreases alpha1(I) collagen mRNA levels and repletion of amino acids induces rapid re-expression of alpha1(I) mRNA. In these studies, we examined the requirements for individual amino acids on the regulation of alpha1(I) collagen mRNA. We found that re-expression of alpha1(I) collagen mRNA was critically dependent on cystine but not on other amino acids. However, the addition of cystine alone did not result in re-expression of alpha1(I) collagen mRNA. Following amino acid depletion, the addition of cystine with selective amino acids increased alpha1(I) collagen mRNA levels. The combination of glutamine and cystine increased alpha1(I) collagen mRNA levels 6.3-fold. Methionine or a branch-chain amino acid (leucine, isoleucine or valine) also acted in combination with cystine to increase alpha1(I) collagen mRNA expression, whereas other amino acids were not effective. The prolonged absence of cystine lowered steady-state levels of alpha1(I) collagen mRNA through a mechanism involving decreases in both the rate of gene transcription as assessed by nuclear run-on experiments and mRNA stability as assessed by half-life determination in the presence of actinomycin D. The effect of cystine was not mediated via alterations in the level of glutathione, the major redox buffer in cells, as determined by the addition of buthionine sulphoximine, an inhibitor of gamma-glutamylcysteine synthetase. These data suggest that cystine directly affects the regulation of alpha1(I) collagen mRNA.

Differential effect of the amino acid cystine in cultured mammalian and bacterial cells exposed to oxidative stress

The effect of cystine in the cytotoxic response of cultured Chinese hamster ovary and Escherichia coli cells to challenge with hydrogen peroxide has been investigated. It was round that this amino acid could either protect or sensitize cells, depending on the cellular system. In fact, although a reduction in the growth-inhibitory effect of hydrogen peroxide was observed in mammalian cells, a marked increase in the susceptibility to oxidative stress was induced by cystine in bacteria. None of the amino acid precursors of glutathione, e.g., glutamate, glycine or cysteine, afforded protection in the mammalian cell system, whereas cysteine, but not glycine or glutamate, markedly sensitized bacteria to hydrogen peroxide-induced cell killing. In mammalian cells, methionine, an amino acid which is converted to cysteine, was alse unable to modify the oxidative response. The results presented indicate that cystine displays differential effects in oxidatively injured mammalian or bacterial cells and suggest that the mechanism whereby the amino acid modulates the lethal action of hydrogen peroxide differs in the two cellular systems.

Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source.

NifQ- and Mol- mutants of Klebsiella pneumoniae show an elevated molybdenum requirement for nitrogen fixation. Substitution of cystine for sulfate as the sulfur source in the medium reduced the molybdenum requirement of these mutants to levels required by the wild type. Cystine also increased the intracellular molybdenum accumulation of NifQ- and Mol- mutants. Cystine did not affect the molybdenum requirement or accumulation in wild-type K. pneumoniae. Sulfate transport and metabolism in K. pneumoniae were repressed by cystine. However, the effect of cystine on the molybdenum requirement could not be explained by an interaction between sulfate and molybdate at the transport level. Cystine increased the molybdenum requirement of Mol- mutants for nitrate reductase activity by at least 100-fold. Cystine had the same effect on the molybdenum requirement for nitrate reductase activity in Escherichia coli ChlD- mutants. This shows that cystine does not have a generalized effect on molybdenum metabolism. Millimolar concentrations of molybdate inhibited nitrogenase and nitrate reductase derepression with sulfate as the sulfur source, but not with cystine. The inhibition was the result of a specific antagonism of sulfate metabolism by molybdate. The effects of nifQ and mol mutations on nitrogenase could be suppressed either by the addition of cystine or by high concentrations of molybdate. This suggests that a sulfur donor and molybdenum interact at an early step in the biosynthesis of the iron-molybdenum cofactor. This interaction might occur nonenzymatically when the levels of the reactants are high.

Effect of Cystine on the Metabolism of Methionine in Rats

Effect of Cystine on the Metabolism of Methionine in Rats

Effect of cystine, selenium, and fish protein on the toxicity and metabolism of methylmercury in rats

Investigations were made of the effect of 0.4% cystine, 0.6 ppm selenium, and fish protein on the toxicity and metabolism of mercury from methylmercuric chloride in male and female weanling rats. When diets with 10% protein and adequate amounts of other nutrients contained 25 ppm mercury, cystine reduced toxicity, selenium as sodium selenite had a greater effect in reducing toxicity, and the combination of cystine and selenium produced a considerably greater additive effect, as measured by increased growth and survival time. Toxicity signs were reduced when fish protein replaced casein in the basal diet, and a 20% protein level from either source reduced toxicity symptoms as compared to a 10% protein level. Cystine, selenium, and fish protein did not inhibit mercury toxicity by increasing its elimination from the body via the urine and feces and, in fact, slightly more mercury was retained when cystine and selenium were added to diets. Few differences were found in the deposition of mercury in tissues that could be attributed to cystine, selenium, and fish protein. The major difference found was in one experiment in which mercury concentrations in the kidney were considerably lower when diets contained cystine, selenium, and fish protein. Possible explanations for the effects observed in these studies included a reduction in mercury accumulation and, hence, damage in the kidney, complexing of mercury by the additives evaluated, and conversion of organic mercury to the less toxic inorganic form.

Effect of Cystine on Fertilization Membrane Development

The fertilization membrane of sea urchin embryos are formed by the elevation of the vitelline membrane to which cortical material fuses. As was shown by Monroy the addition of cystine does not prevent either the elevation of the vitelline membrane or the adherence of the cortical material, but the cortical material does not fuse with the vitelline membrane.

Studies on the death of staphylococcus suspended in saline solution No. 2

In the previous paper, the death phenomenon of staphylococci in saline solution was described and the results of the studies on the biological nature of this phenomenon were reported.This phenomenon is not only interesting in its biological nature but also seems to have some important significances because saline suspensions of staphylococci are usually employed as the control sample in various kinds of biological reactions. In these reaction, the control sample of bacterial suspensions should be in the resting condition under which the bacterial cells would not be killed and at the same time not proliferate.From this point of view, experiments were carried out to study on the inhibitors for the above mentioned death of staphylococcus in saline solution and to devise the idealistic medium for the suspension of staphylococcus composing of minimum set of amino acids.Results are as follows:(1) The death rate of staphylococcus in saline suspension can be slightly decreased if glucose is added to the saline medium.(2) If the staphylococci are suspended in simple casamino acid medium at 37°C and shaking-incubated, there occurs neither death nor growth of cocci even after overnight incubation.(3) Of the eight kinds of amino acids which are known to be required as the essential nutrient for the propagation of the St. aureus, three amino acids namely 1-tryptophane, glutamic acid, and hystidine which have been reported to promote the propagation of the staphylococci but are not indispensable, are proven to be unable to inhibite the death of staphylococci even when all of them are added into the saline medium.(4) Subsequently four amino acids; 1-arginine, 1-cystine, 1-glycine and 1-proline, which are known to be indispensable for the propagation of the staphylococci, were examined for their ability to inhibit the death of staphylococci when they were added to saline medium. The former three were proven to give a considerable suppressing effect to this phenomenon, and among them, the effect of cystine was the strongest. But the latter one could not show any effect.(5) Although the above mentioned suppressing effects of these three amino acids are less than that of casamino acid, they could show a remarkable effect as much as equivalent to that of the casamino acid when all these three amino acids were added together.(6) Consequently the mixture of the above mentioned 3 amino acids and glucose could be recommended as the most suitable medium for staphylococcus suspension.

The biosynthesis of penicillin. 7. Further experiments on the utilization of L-and D-valine and the effect of cystine and valine analogues on penicillin synthesis.

The biosynthesis of penicillin. 7. Further experiments on the utilization of L-and D-valine and the effect of cystine and valine analogues on penicillin synthesis.

The effect of cystine and methionine, added separately or together, on the biological value of the proteins of dried skim milk.

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Effect of cystine and methionine on healing of experimental wounds.

SummaryThe effect of methionine and cystine on the healing index of standard experimental wounds in rats was determined. Since both amino acids have the same effect, per equivalent of sulfur, it is concluded that methionine is converted to cystine before being used in the healing process. When the utilization of methionine is blocked by ethionine, cystine is ineffective, indicating that some methionine, per se, is required for the healing of wounds. There appears to be a correlation between the healing index and the retention of amino acid sulfur in excess of that expected on the basis of nitrogen retention.

EFFECT OF CYSTINE AND THREONINE ON THE GROWTH OF RATS RECEIVING TRYPTOPHAN-DEFICIENT RATIONS

EFFECT OF CYSTINE AND THREONINE ON THE GROWTH OF RATS RECEIVING TRYPTOPHAN-DEFICIENT RATIONS

The Effect of Cystine on Human Milk Production

The Effect of Cystine on Human Milk Production

The Effect of Cystine and Casein Supplements upon the Nutritive Value of the Protein of Raw and Heated Soy Beans

The Effect of Cystine and Casein Supplements upon the Nutritive Value of the Protein of Raw and Heated Soy Beans