• Journal of Microbiology and Biotechnology
• /
• v.18 no.5
• /
• pp.983-989
• /
• 2008

Human insulin is a hormone well-known to regulate the blood glucose level. Recombinant preproinsulin, a precursor of authentic insulin, is typically produced in E. coli as an inactive inclusion body, the solubilization of which needs the addition of reducing agents such as $\beta$-mercaptoethanol. To make authentic insulin, recombinant preproinsulin is modified enzymatically by trypsin and carboxypeptidase B. The effects of $\beta$-mercaptoethanol on the formation of human insulin derivatives were investigated in the enzymatic modification by using commercially available human proinsulin as a substrate. Addition of 1 mM $\beta$-mercaptoethanol induced the formation of various insulin derivatives. Among them, the second major one, impurity 3, was found to be identical to the insulin B chain fragment from $Phe_1$ to $Glu_{21}$. Minimization of the formation of insulin derivatives and concomitant improvement of the production yield of human insulin were achieved by the addition of hydrogen peroxide. Hydrogen peroxide bound with $\beta$-mercaptoethanol and thereby reduced the negative effects of $\beta$-mercaptoethanol considerably. Elimination of the impurity 3 and other derivatives by the addition of over 10 mM hydrogen peroxide in the presence of $\beta$-mercaptoethanolled to a 1.3-fold increase in the recovery efficiency of insulin, compared with those for the case without hydrogen peroxide. The positive effects of hydrogen peroxide were also confirmed with recombinant human preproinsulin expressed in recombinant E. coli as an inclusion body.

• Proceedings of the KSAR Conference
• /
• 2002.06a
• /
• pp.74-74
• /
• 2002

This study was undertaken to evaluate the effects of β-mercaptoethanol on lipid peroxidation and fertilization ability in vitro by xanthine (X)-xanthine oxidase (XO) system in boar spermatozoa frozen-thawed. When spermatozoa were inseminated in medium with X and/or XO, the penetration rates in all conditions were higher in medium with that than without β-mercaptoethanol. However, significant differences were not observed between medium with and without β-mercaptoethanol. The lipid peroxidation of sperm was evaluated on the basis of malondialdehyde (MDA) production. (omitted)

• Journal of Embryo Transfer
• /
• v.12 no.3
• /
• pp.269-276
• /
• 1997

The objective of this study was to investigate the effects of thiol compounds with bovine oviduct epithlial crlls(BOEC) co culture on development and intracellular glutathione(GSH) concentrations of bovine embryos derived from IVM /IVF oocytes. In experiment 1 and 2, embryos developed to 2~8 cell stage after in vitro fertilization were co-cultured with BOEC in CR$_1$aa with or without $\beta$-mercaptoethanol($\beta$-ME) and cysteamine. The percentage of embryos that developed to morulae and blastocysts in 0,10, 25 and 5O$\pi$M $\beta$-ME with BOEC was 48.1, 64.0, 72.9 and 75.9%, respectively. Twenty-five and 5O$\pi$M $\beta$-ME groups were significantly higher than in 0 and 1O$\pi$M $\beta$- -ME groups(P$\pi$M cysteamine with BOEC was 50.0, 53.2, 72.0 and 66.7%, respectively. Fifty $\pi$M cysteamine group was significantly higher than any other groups (P$_4$aa with 0 and 5O$\pi$M $\beta$-ME or cysteamine were 68.5, 77.8, 78.7 and 80.0pM, respectively. Fifty $\pi$M $\beta$-ME group was significantly higher than that of control(P<0.05), but cysteamine group was not. Cell numbers of blastocysts were not difference in all experimental groups. These experiments indicate that $\beta$-ME and cysteamine with BOEC co-culture can affect the development and intracellular GSH concentrations of bovine embryos produced by IVM /IVF docytes.

• Development and Reproduction
• /
• v.10 no.4
• /
• pp.239-245
• /
• 2006

Experiments were conducted to determine the effects of beta-mercaptoethanol(${\beta}-ME$) supplements to the maturation medium on in vitro fertilization(IVF) and intracellular glutathione(GSH) concentration. Bovine cumulus-intact oocytes were matured in TCM-199 medium containing FBS, hormonal supplements, and ${\beta}-ME$(0, 25 and $50\;{\mu}M$) for 12h and 24 h. After culture, cumulus-free matured oocytes were co-incubated with frozen-thawed spermatozoa for 24h. Maturation rate increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant differences among treatment groups. Also, increases(p<0.05) in intracellular GSH concentration before and after fertilization were observed in $50\;{\mu}M\;{\beta}-ME$ supplements to the maturation medium. Male pronuclear formations after IVF was increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant difference among treatment groups. In conclusion, supplementing ${\beta}-ME$ into the maturation medium increased maturation rates, fertilization rates, and intracellular GSH concentrations.

• Journal of Animal Science and Technology
• /
• v.47 no.3
• /
• pp.363-370
• /
• 2005

Experiments were conducted to determine the effects of beta-mercaptoethanol ($\beta$-ME) supplements to the in vitro maturation (IVM) medium on in vitro fertilization (IVF) and intracellular glutathione (GSH) concentration. Porcine cumulus-intact oocytes were matured in TCM-I99 medium containing porcine follicular fluid, sodium pyruvate, D-glucose, FBS, hormonal supplements, and $\beta$-ME (0, 25, 50 and 100 ${\mu}$M) for 36 to 46h. After culture, cumulus-free matured oocytes were co-incubated with epididymal spermatozoa for 18h. There were no significant differences in the maturation rate among treatment groups. However, increases (P < 0.05) in intracellular GSH concentration before and after. fertilization were observed in 50 ${\mu}$M $\beta$-ME supplements to the IVM medium. Also, increases (P < 0.05) in male pronuclear formation after IVF were observed in same treatment group. In conclusion, supplementing $\beta$-ME into the IVM medium increased intracellular GSH concentrations and increased fertilization in vitro.

• Journal of Embryo Transfer
• /
• v.12 no.3
• /
• pp.277-282
• /
• 1997

The purpose of this experiment was to determine the effects of thiol compounds, $\beta$-mercaptoethanol($\beta$-ME) and cystearrone with buffalo rat liver cell(BRLC) co-culture on the development and intracellular glutathione(GSH) concentrations of bovine embryos produced by in vitro inaturation(IVM) and in vitro fertilization(IVF). Bovine IVM /IVF embryos developed to 2~8 cell stage were co-cultured with BRLC in GRlaa with or without thiol compounds. The developmental rate beyond morulae stage in CRlaa containing 0, 10,25 and 50$\pi$M $\beta$-ME with BRLG were 63.0, 74.0, 72.3 and 77.1%, respectively. And the developmental rate with 0, 25, 50 and 75$\pi$M cystearnine with BRLC were 69.6, 77.6, 81.0 and 76.8%, respectively. The developmental rate beyond morulae stage of GRlaa containing thiol compound with BRLG group was higher than that of control group. The intracellular GSH concentrations of blastocysts cultured for 5 days in GRlaa containing 0 and 50$\pi$M $\beta$-ME or cysteamine with BRLG were 81.2 and 86.4, 83.2 and 84.2pM, respectively. The intracellular GSH concentrations of blastocysts in GRlaa containing thiol compounds with BRLG was slightly higher than that of control group The cell numbers of blastocysts were not difference in all experimental groups. These results indicate that thiol compounds with BRLG co-culture was increased the percentage of developed into morulae and blastocysts, and intracellular GSII concentrations of blastocysts embryos.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.3
• /
• pp.253-258
• /
• 1996

Stabilities of sweets potato f-amylase on various reagents were studied. The enzyme was stabilized by bovine serum albumin, Triton X-100 and 2-mercaptoethanol of 0.04%. Among them, bovine serum albumin was the most effective. And enzyme stability was increased by using the deairated solution. The enzyme activity was remained 0% in the absence of glycerol, 25% in the presence of 20% glycerol and 50% in the presence of 40% glycerol at 37$^{\circ}C$, for 15 hours in pH 11. SDS inhibited the enzyme, and 2-mercaptoethanol and dithiothreitol stabilized it.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.5
• /
• pp.615-621
• /
• 2002

We investigated the effects of the mitogen supplements of 3 types, pokeweed mitogen (PWM), phytohemagglutinin (PHA) and concanavalin A (ConA), to a whole blood culture system on the number of metaphase spreads obtained in perinatal bovine chromosome analysis. In addition, the supplementation of ${\beta}$-mercaptoethanol (${\beta}$-ME) and FBS was examined in such system. Significant differences (p<0.05) were seen in the number of metaphase spreads with PHA stimulation compared to both PWM and ConA stimulation. When examined the effects of ${\beta}$-ME supplementation, the number of metaphase spreads was significantly (p<0.05) increased at $30{\mu}M$ ${\beta}$-ME compared to control. When evaluated FBS supplementation during PWM stimulation, no significant effect of the supplementation was found. Finally, the effects of the cortisol concentration (10-20, 20-30 and >30 ng/ml) of the blood samples were examined. There was no significant effect of cortisol concentration (p>0.05) among these 3 cortisol concentration groups. The mean percentages of normal metaphase plates (2n=60) from each calf 1) with ${\beta}$-ME, 2) without ${\beta}$-ME and 3) with FBS stimulated with PWM were not significantly different (p>0.05). In conclusion, these findings may be useful in cytogenetic screening programs for not only perinatal calves but also for mature cattle.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.1
• /
• pp.35-41
• /
• 2009

This study was undertaken to evaluate how ${\beta}$-mercaptoethanol (bME), an exogenous antioxidant, interacts with preantral follicles cultured in vitro. Mouse primary or secondary follicles were cultured in glutathione (GSH)-free or GSH-containing medium supplemented with bME of various concentrations, and the growth of preantral follicles, the maturation of intrafollicular oocytes and preimplantation development after parthenogenesis were monitored. In experiment 1, 0, 25, 50 or 100 ${\mu}M$ bME was added to culture medium supplemented with 100 ${\mu}M$ GSH or not. When secondary follicles were cultured in GSH-free medium, no significant change in follicle growth was detected after bME addition. However, exposure to bME in the presence of GSH significantly inhibited both follicle growth and oocyte maturation. Such detrimental effect became prominent in primary follicles and bME strongly inhibited follicle growth in the absence of GSH. In conclusion, there are stage-dependent effects of bME on follicle growth and oocyte maturation, and selective use of antioxidants contributes to establishing an efficient follicle culture system.

• Korean Journal of Animal Reproduction
• /
• v.26 no.3
• /
• pp.263-273
• /
• 2002

This study was undertaken to evaluate the effects of $\beta$-mercaptoethanol ($\beta$-ME) on lipid peroxidation and fertilization ability in vitro by xanthine (X) - xanthine oxidase (XO) system in boar spermatozoa frozen-thawed. The boar spermatozoa were treated with X and/or XO, and the spermatozoa viability were measured by the eosin-nigrosin stain method. In control group, level of vitality in boar spermatozoa were higher than in medium with X, XO and X+XO groups. No significant differences, however, were observed under the all conditions. The percentage of spermatozoa that reached acrosome reaction were significantly (P<0.05) higher in sperm treated without that than with $\beta$-ME under the all conditions. On the other hand, when spermatozoa were inseminated in medium with X and/or XO, the penetration rates in all conditions were higher in medium with that than without $\beta$-ME. However, significant differences were not observed between medium with and without $\beta$-ME. The lipid peroxidation of sperm was evaluated on the basis of malondialdehyde (MDA) production. The MDA were higher in sperm treated without that than with $\beta$-ME under the above all conditions. However, significant differences were not observed between medium with and without $\beta$-ME. Sperm-SH group were higher detected in medium with that than without $\beta$-ME under the all conditions. The activity of sperm binding to Bona pellucida was also evaluated through binding to salt-stored porcine oocytes. In control group, sperm binding to zona pellucida were significantly (P<0.05) higher than in medium with X+XO groups. The sperm binding in all conditions were higher in medium with that than without $\beta$-ME. However, significant differences were not observed between medium with and without $\beta$-ME. These results suggest that addition of $\beta$-ME in X-XO system may play a positive role in improving of fertilization ability in vitro.