• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.195-200
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• 2022

Sulfur is an essential element in plants, including amino acids, vitamin synthesis, and acting as an antioxidant. However, the interaction between endogenous sulfur and proline synthesis has not been yet fully documented. White clover (Trifolium repens L.) is known as a species highly sensitive to sulfate supply. Therefore, this study aimed to elucidate the role of sulfur in regulating proline metabolism in relation to ammonia detoxification and hydrogen peroxide (H₂O₂) accumulation in white clover. The detached leaves of white clover were immersed in solution containing different concentration of sulfate (0, 10, 100, and 1000 mM MgSO₄). As MgSO₄ concentrations were increased, the concentration of H₂O₂ increased up to 2.5-fold compared to control, accompanied with H₂O₂ detection in leaves. Amino acid concentrations significantly increased only at higher levels (100 and 1000 mM MgSO₄). No significant difference was observed in protein concentration. Proline and ∆^1-pyrroline-5-carboxylate (P5C) concentrations slightly decreased at 10 and 100 mM MgSO₄ treatments, whereas it rapidly increased over 1.9-fold at 1000 mM MgSO₄ treatment. Ammonia concentrations gradually increased up to 8.6-fold. These results indicate that exogenous sulfur levels are closely related to H₂O₂ and ammonia synthesis but affect proline biosynthesis only at a higher level.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.109-115
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• 2023

Ammonium (NH₄⁺) serves as a nitrogen source, but its elevated levels can hinder plant growth and production. Excess NH₄⁺ with α-ketoglutarate is assimilated into glutamate, a precursor of proline and glutathione (GSH). This study aimed to investigate the effects of excessive NH₄⁺ on the regulation of proline and GSH synthesis. Detached leaves from oilseed rape (Brassica napus L.) were fed with 0, 50, 100, 500, and 1000 mM NH₄Cl for 16 h. As the NH₄⁺ concentrations increased, the leaves exhibited progressive wilting and yellowing. Furthermore, total carotenoid and chlorophyll concentrations declined in response to all NH₄⁺ treatments, with the lowest levels observed in 1000 mM NH₄⁺ treatment. Hydrogen peroxide (H₂O₂) concentration showed a minor increase at low NH₄⁺ concentration (50 and 100 mM) treatments but a significant increase at high NH₄⁺ (500 and 1000 mM), which was consistent with the localization of H₂O₂. Amino acid concentrations increased with increasing in NH₄⁺ concentration, while the protein concentration displayed the opposite trend. Proline and cysteine concentrations exhibited a gradual increase in response to increasing NH₄⁺ concentrations. However, GSH concentrations rose only in the 50 mM NH₄⁺ treatment and decreased in the 500 and 1000 mM NH₄⁺ treatments. These results indicate that excessive NH₄⁺ is primarily assimilated into proline, while GSH synthesis is adversely affected.

• Journal of the Korean Chemical Society
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• v.58 no.4
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• pp.351-358
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• 2014

Anionic (sodium lauryl sulphate, NaLS) cationic (cetyl ammonium bromide, CTAB) and non-ionic (Tween-80) surfactants have been found to inhibit the rate of oxiadation L-proline and L-methionine by alkaline $KMnO_4$. A first order dependence of rate of oxidation was observed with respect to $MnO_4{^-}$. The order of reaction in substrate and alkali was found to be fractional nearby 0.65 and 0.55 in Aminoacid and $OH^-$, respectively. An aggregation/association between $MnO_4{^-}$ and surfactant has been confirmed spectrophotometrically. A mechanism, involving kinetically inactive [$MnO_4{^-}$ surfactant] aggregate and consistent with kinetic data, has been proposed. The effect of surfactants has been discussed in terms of hydrophobic and electrostatic interactions.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.51-55
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• 1998

The experiment was conducted to elucidate the growth response of rice seedling to heavy metals, copper and zinc. The copper and zinc concentration in rice seedling was 50mg/l and 100mg/l, respectively. Germination. chlorophyll and organic compounds were investigated in seedling of rice with or without heavy metals. Root growth and germination were inhibited at 50mg/l Cu and at 100mg/l compared to control and such reduction in growth was more remarkable at 100mg/l Zn than at 50mg/l Cu. Chlorophyll content was slightly reduced at both 50mg/l Cu and 100mg/l Zn. Malic acid was remarkably increased at 50mg/l Cu compared with that at Zn 100mg/l regardless of rice cultivars. The content of organic acids such as succinic, citric, and malic acid and free proline was increased with treatment of copper and zinc.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1165-1172
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• 2002

The effects of salicylic acid(SA) and water deficit on growth and proline accumulation were investigated in cucumber(Cucurmis sativus L.) seedlings. Exogenous application of SA(100 $\mu$M-1 mM) led to a noticeable decrease in root and shoot growth, and dry weight of seedlings. Anatomical observation on leaf of cucumber revealed that the thickness of all leaf tissue components decreased in SA-treated plants. The effect was most pronounced on the width of the adaxial epidermis. In the separate effects of SA(0, 100, 500 and 1000 $\mu$M) and water deficit induced by PEG(0, 4.4, 7.0 and 9.6 %) on growth, the water deficit treatments had greater effects on growth traits than SA. Combinations of SA and PEG(SA+PEG) decreased shoot and root dry matter, and root length. Proline increased slightly in SA-treated seedlings, but exhibited a marked increase in water deficit application. Combinations of SA+PEG induced higher proline in both shoots and roots than SA stress alone. Shoots had higher proline than roots. Our data support a role of SA potentiating the osmotic stress response of germinating cucumber seedling.

• Journal of the Korean Chemical Society
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• v.22 no.6
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• pp.386-395
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• 1978

The rates of the forward mutarotation of poly(trans-5-methyl-L-proline) in trifluoro-ethanol and of the reverse mutarotation in trifluoroethanol-n-butanol (1:4 v/v) have been measured at a number of temperatures and polymer concentrations. It was found that both mutarotations are of first-order with respect to the polymer concentration. A modified Arrhenius equation to evalute the activation energy was derived for the reaction kinetics, in which the relation between the measured physical properties and concentration, and the order of tle reaction are uncertain. The activation energies for the forward and reverse mutarotation were found to be 32.5 and 33.5 kcal per residue mole, respectively, which are about 10 kcal per residue mole higher than the $E_a$ for the mutarotation of polyproline (the resonance energy of amide bonds). The excessive quantity of the activation energy was attributed to the steric barrier between carbonyl and methyl groups during the cis-trans isomerization of amide bonds in the polymer.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.323-329
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• 2023

In this study, Proline pentamer model was used to investigate change in the dihedral angle, intramolecular hydrogen bonding and formation energies during structural optimization. L-Proline (LP, as an imino acid residue) pentamers having four conformation types [β: φ/ψ=t−/t+, α: φ/ψ=g−/g−, PP_II: φ/ψ=g−/t+ and Plike: φ/ψ= g−/g+] were carried out by QCC [B3LYP/6-31G(d,p)]. The optimized structure and formation energy were examined for designated structure. In LP, P-like and PP_II types did not change by optimization, and β types were transformed into PP_II having no H-bond independently of the designated ψ values. PP_II was more stable than P-like by about 2.2 kcal/mol/mu. The hydrogen bond distances of d2(4-6) type H-bonds were 1.94 - 2.00Å. In order to understand the processes of the transformations, the changes of φ/ψ, distances of NH-OC (d_NH/CO) and formation energies (ΔE, kcal/mol/mu) were examined.

• Journal of Plant Biology
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• v.36 no.3
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• pp.211-218
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• 1993

Plant regeneration was accomplished from protoplast culture of rice (Oryza sativa L. cv. Taebaeg). Embryogenic callus was induced from mature seed on MS medium containing 5 mM proline, 2.5 mg/L 2,4-D, 30 g/L sucrose in the dark at 28$^{\circ}C$ and used to establish embryogenic cell suspension culture. Suspension cells were subcultured every one week in N6 medium supplemented with 5 mM proline, 200 mg/L casein hydrolysate, 2.5 mg/L 2,4-D and amino acids of AA medium. Suspension cultures were composed of cells that were densely cytoplasmic, potentially embryogenic and were at least maintained for more than 6 months in liquid medium. Protoplasts were isolated from fast-growing suspension culture cells and cultured in a slightly modified KpR medium by mixed nurse culture. Isolated protoplasts began to divide within 5~7 days and thereafter, protoplast-derived calli were sequentially transferred to callus proliferating medium that soft agar MS medium contained 2 mg/L 2,4-D and produced distinct embryogenic cells. Microcolonies were then transferred to solid medium which consisted of MS medium containing 5 mg/L kinetin, 1 mg/L NAA, 1 mg/L ABA, 30 g/L sucrose and 10 g/L sorbitol under fluorescent light. Mulitple shoots of 4~5 per callus emerged and were transferred to hormone-free MS medium for root initiation. Thereafter, The plantlets were transferred to pots of soil to mature in the culture room.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1173-1181
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• 2002

The present study was undertaken to investigate the effect of low temperature and salicylic acid(SA) on the chilling tolerance of acclimated and nonacclimated cucumber(Cucurmis sativus L.) seedlings. The acclimation phenomenon was characterized in chilling-sensitive cucumber seedlings and found to have a significant effect on the survival and shoot dry weights. The injuries experienced by the acclimated seedlings in the third leaf stage were on average smaller by half than those experienced by the nonacclimated seedlings. Chilling also caused a large increase in the free proline levels, regardless of the acclimation status. Exogenous treatment with SA(0.5mM) resulted in improved growth and survival of the nonacclimated chilled seedlings, indicating that SA induced chilling tolerance and SA and acclimation had common effects. The application of cycloheximide in the presence of SA restored the acclimation-induced chilling tolerance. The elevated proline level observed in the cold-treated and SA-treated plants was more pronounced in the light than in the dark at a chilled temperature, indicating that endogenous proline may play a role in chilling tolerance by stabilizing the water status in response to chilling. From these results it is suggested that SA provided protection against low-temperature stress by increasing the proline accumulation, and pre-treatment with SA may induce antioxidant enzymes leading to increased chilling tolerance.

• KSBB Journal
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• v.24 no.3
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• pp.246-252
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• 2009

Rice cells were transformed to express human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) using RAmy3D promoter. hCTLA4Ig was produced and secreted into culture media inducibly when sugar was depleted. The obstacles of this system are the cell death and release of proteases by sugar starvation. These problems resulted in the losses of stability and productivity of hCTLA4Ig. Therefore, the effects of proline as an inhibitor of cell death were investigated. When 4 mM proline was added in sugar-free media, the cell death and release of proteases were reduced. As a consequence, the production of hCTLA4Ig was enhanced. In addition, the effects of protein stabilizers such as gelling agents were studied. It was found that the application of 0.01 g/L gelatin led to an increase in hCTLA4Ig production. This increase might be originated from the stabilization of hCTLA4Ig. In conclusion, the production of hCTLA4Ig could be enhanced by the additions of proline and gelatin in transgenic rice cell cultures.