• Biomolecules & Therapeutics
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• v.30 no.2
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• pp.184-190
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• 2022

Targeting the cystine/glutamate exchange transporter, system x_c^-, is a promising anticancer strategy that induces ferroptosis, which is a distinct form of cell death mediated by iron-dependent lipid peroxidation. The concentration of ⳑ-cystine in culture medium is higher than the physiological level. This study was aimed to evaluate the effects of ⳑ-cystine concentration on the efficacy of ferroptosis inducers in hepatocellular carcinoma cells. This study showed that treatment with sulfasalazine or erastin, a system x_c^- inhibitor, decreased the viability of Huh6 and Huh7 cells in a dose-dependent manner, and the degree of growth inhibition was greater in medium containing a physiological ⳑ-cystine concentration of 83 µM than in commercial medium with a concentration of 200 µM ⳑ-cystine. However, RSL3, a glutathione peroxidase 4 inhibitor, decreased cell viability to a similar extent in media containing both ⳑ-cystine concentrations. Sulfasalazine and erastin significantly increased the percentages of propidium iodide-positive cells in media with 83 µM ⳑ-cystine, but not in media with 200 µM ⳑ-cystine. Sulfasalazine- or erastin-induced accumulation of lipid peroxidation as monitored by C11-BODIPY probe was higher in media with 83 µM ⳑ-cystine than in media with 200 µM ⳑ-cystine. In contrast, the changes in the percentages of propidium iodide-positive cells and lipid peroxidation by RSL3 were similar in both media. These results showed that sulfasalazine and erastin, but not RSL3, were efficacious under conditions of physiological ⳑ-cystine concentration, suggesting that medium conditions would be crucial for the design of a bioassay for system x_c^- inhibitors.

• Journal of Sericultural and Entomological Science
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• v.2
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• pp.1-31
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• 1962

The purpose of this treatise is to prove the presence of cystine in silk fiber through wide sampling throughout all the sericultural processes of Bombyx mori.; also to show that disulfide cross linkages exist in the silk fiber. The conclusions reached were as follows: 1. Crystalline cystine was obtained from silk fibroin using Folin's Method. 2. Analytical data showing the cystine content of silk fiber and its related materials were obtained using Sullvan's Method as follows: Material Percent Cystine A. Mulberry leaf protein 0.175 B. Silkworm egg 0.33 C. Silkworm Body, matured, fat extracted, without silk gland 0.41 D. Silk gland, matured 1.23 E. Silkworm feces none F. Silkworm pupa, fat extracted 0.30 G. Silkworm moth, fat extracted 0.60 H. Raw Silk 0.22 I. Fibroin 0.175 J. Sericin 0.30 3. The presence of cystine in the silkworm was substantiated the existence of 0.175 % methionine in mulberry leaves and 0.12% methionine in the silk gland. 4. Part of the sulfhydryl compounds in the silk gland is believed to transfer to serine and methionine, with the former being secreted into the liquid silk finally as silk fiber and the latter used for nutritive purposes in the growing of silk gland tissue. 5. The cystine content is variable by mulberry species, silkworm species, sex, breeding process, and other culturing environments. 6. Hybrid silkworms require more nutritive amino acids for effective growth than the original parents, and secrete less of them as silk fiber. 7. From such an observation, the amino acid composition of silk fiber is believed to be fairly flexible. Cystine if included in the amorphous part of the fiber, especially in sericin. 8. The result from enriching the silkworm diet with pure cystine or wool cystine did not result in any advantage, therefore it is believed that the natural cystine and methionine contents in the mulberry leafaregoodenoughforsilkwormnutrition. 9. The disulfide cross linkage in silk fiber was verified by using the Harris Method. Contraction took place following the treatment of the fiber with various salts and acids. Comparisons were made with wool fiber. 10. During these experiments, the fibrious structure of silk fiber and the net-globular liquid form were photographed microscopically. It is believed that the globules of liquid silk are net-formed by the inter attraction of the OH ion of the globular peptide and the H ion of water as shown by the hair cracking behavior of the film. The net-globular protein precipitation from the mulberry protein solution showed that mulberry is a proper diet for the formation of fibrous protein in the silk fiber. 11. The significance of the presence of cystine in silk fiber as emphasized in this paper should result in modification of the general conception that cystine is absent from this fiber. NOTICE: A part of this treatise was presented at the annual Korea Sericultural Society meeting held in 1961.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.2 s.30
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• pp.137-145
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• 1989

The purpose of this study was to investigate the effect of the permenent pleats finish on the cystine contents and the physical properties of wool fabrics. Monoethanolamine Sulfite (MEAS) was used as a reducing agent. Cystine contents of the fabrics were determined after the fabric was treated with various MEAS concentrations and steamset time. The cystine contents were increase as the MEAS concentrations were increased. The cystine contents were also increased with steamset time. As the settability showed close relationship with the cystine contents, breakdown and rebuilding of the cystine linkage was thought to play an important role for the settability. Physical properties such as shrink resistance, crease recovery angle and tensile strength were increased as the MEAS concentration was increased. As the stramset time was increased, shrink resistance and crease recovery angle were in creased.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.86-97
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• 1997

Purified diets containing 5 graded levels of methionine + cystine were fed to young, growing and finishing pigs to determine the methionine + cystine requirement for growth and maintenance. A model was developed to subdivide the methionine + cystine requirement for maintenance from requirement for growth. From this model, the methionine + cystine requirement for growth was 8.633, 10.260 and 9.293 g/kg live weight gain and the maintenance requirement was 0.049, 0.016 and 0.019 g per unit of metabolic body size at each stage of growth, respectively. In the young pigs, the methionine + cystine requirement for growth was 0.491 g/g N gain and the maintenance requirement was 0.059 g per unit of metabolic body size. The breakpoint of plasma methionine + cystine concentrations was 3.888, 6.935 and 8.116 g/d, respectively. Expected requirements obtained from these formulae were in general agreement with previous estimates. Based on the weight gain vs N gain equation, about 4.44% of the retained protein was comprised of methionine + cystine and compared to 3.31%, the mean methionine + cystine content of pig muscle CP.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.434-442
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• 2008

The objective of this study was to determine the optimum ratio of methionine to methionine plus cystine for growing pigs. A nitrogen balance trial was conducted using a total of 21 barrows (Large WhiteLandrace) over two replicates. The initial body weight was $20.36{\pm}1.22kg$ (mean${\pm}$SD) in the first replicate and $23.54{\pm}1.02kg$ (mean${\pm}$SD) in the second. For each replicate, the 21 pigs were randomly assigned to one of seven dietary treatments with three observations per treatment. The diets included a methionine and cystine-deficient basal diet with all other essential nutrients meeting nutrient requirements and six diets formulated with graded levels of DL-methionine (0.00, 0.03, 0.06, 0.10, 0.13, 0.16%) and $L-Cystine{\cdot}HCl{\cdot}H_2O$ (0.19, 0.15, 0.11, 0.07, 0.04, 0.00%). This resulted in ratios of methionine to methionine plus cystine of 41.3, 29.6, 35.3, 41.2, 46.0, 51.6 and 57.5%. Each experimental period lasted 12 days consisting of a seven-day adaptation period followed by a five-day total collection of urine and feces. During the collection period, pigs were fed 900 g/day for the first replicate and 1,200 g/day for the second replicate. The feed was provided in three equal portions at 0800, 1500, and 2200 h daily. Pigs had ad libitum access to water after feeding. There was a linear (p<0.01) and quadratic (p<0.01) effect on daily gain and feed conversion as the ratio of methionine to methionine plus cystine increased. Pigs receiving the diets providing a methionine to methionine plus cystine ratio of 51.6% had the best daily gain and feed conversion. Plasma urea nitrogen was also lowest for this treatment. Nitrogen retention increased (p<0.01) as the relative proportion of methionine increased up to 51.6% and then a downward trend occurred at 57.5%. The quadratic regression model, as well as one- and two- slope regression line models, were used to determine the optimum ratio of methionine to methionine plus cystine. Eliminating the 35.3% methionine to methionine plus cystine treatment resulted in $R^2$ values in excess of 0.92. The optimal ratio of methionine to methionine plus cystine was estimated to be 54.15% for nitrogen retention and 56.72% for plasma urea nitrogen.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.922-927
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• 1996

In order to investigate heat-induced gelation properties of $\alpha-lactalbumin(\alpha-La),$ total free SH groups, half-cystine, and disulfide bond contents of $\alpha-La$ gels prepared in 0.1M Tris-HCI buffer(pH 8.0) were measured. The samples were heated at $90^{\circ}C$ for 40 minutes under different PH and concentrations of NaCl, $CaCl_2,$ $\alpha-La,$ N-ethylrnaleirnide(NEM), and dithiothreitol(DTT). Total free SH groups were low at high concentrations of $\alpha-La$ and at pH 6.5~8.5, and were $14.72~18.58\mu\textrm{m}ol/g$ and $14.17~16.11\mu\textrm{m}ol/g,$ respectively. Half-cystine contents of NEM-induced gels decreased with increasing concentration of NEM, and were $1.03~39.17\mu\textrm{m}ol/g.$ Disulfide bonds of DTT-induced gels increased with increasing concentration of DTT, and were $70.04~71.80\mu\textrm{m}ol/g$.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.827-838
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• 1997

Optimal substrates and reaction conditions were studied to develop boiled or roasted meat flavor by Maillard reaction under a model system. Sugars for the reactions were xylose, ribose, glucose, lactose, maltose, and sucrose. Amino acids were cystine, cysteine, methionine, lysine, and glycine as the reaction substrates. The reacted solutions were measured their absorbances at 278 nm and 420 nm and were evaluated their sensory properties. Except cysteine, the pentose mixtures with all of the four amino acids showed a faster reaction rate than those mixtures with hexose or disaccharides. pH was decreased rapidly until 8 hours and then changed a little thereafter. Sensory evaluation showed that cystine-lactose or cystine-xylose from single substrate and cystine-lactose-maltose, and cystine-lactose-xylose from mixed substrates reacted at $100^{\circ}C$ for 16 or 20 hours were found to be close to boiled or roasted meat flavor. The volatile compounds from the four selected sugar-amino acid solutions by GC/MS were 8 hydrocarbons, 10 aldehydes, 6 ketones, 7 alcohols, 2 aromatics (benzene), 1 ester, 4 furans, 1 base and 5 sulfur compounds.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.354-358
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• 1997

Some sulfur coompounds dissimilation characteristcs of Thermococcus sp. DT1331 were studied. DT1331 had ether-like lipid compounds in addition to esters in the cell membrane. The specific growth rates of DT1331 decreased with increasing head spaces of the cultures. However, when the ratio of head space volume to medium volume was 5.60, the strain showed no growth. DT1331 showed vigo- rous growth with 1% or more elemental sulfur addition. Cystine could substitute elemental sulfur and DT1331 showed moderate growth with 0.1% or more cystine concentration. The specific growth rate and maximum cell concentration of Thermococcus sp. DT1331 in the presence of elemental sulfur were 0.80 hr$^{-1}$ and 2.0 x 10$^{8}$ cells/ml, respectively, while they were 0.67 hr$^{-1}$ and 1.1 x 10$^{8}$ cells/ml, respectively in the presence of cystine.

• Fashion & Textile Research Journal
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• v.1 no.4
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• pp.393-396
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• 1999

The purpose of this study was to suggest the knowledge and scientific information of the damage and improvement according to hair coloring manipulation. The study investigated variations of mechanical, nourishment(amino acid cystine) shape of cuticle characteristics according to hair coloring during 40, 50 minute. The results were as follows; Tensile strength was decreased variations of 6.62%, 13.68%, extension rate was increased variations of 10.58%, 12.28%, thickness was increased variations of 9.15%, 15.64% in 40 min. and 50 min. hair coloring. Content of amino acid cystine was lowered variations of 23.00%, 30.49% according to time of manipulation. A shape of cuticles was disfigured and brocken by reason of hair coloring manipulation.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.615-619
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• 2003

Cystinosis, an autosomal recessively inherited lysosomal storage disease, results from impaired transport of the amino acid cystine out of cellular lysosomes. The consequent accumulation and crystallization of cystine destroys tissues, causing growth retardation, Fanconi syndrome, renal failure, eye problems, and endocrinopathies. The gene for cystinosis, CTNS, was mapped to chromosome 17p13. The diagnosis of cystinosis was made by measuring the leukocyte cystine content. The presence of typical corneal crystals on slit-lamp examination is also diagnostic. Since treatment with cysteamine has proved extremely effective, early diagnosis and treatment are critical aspects. We experienced a typical case of cystinosis in a 12-year-old boy with growth retardation.