• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1978.10a
• /
• pp.206.4-206
• /
• 1978

By utilizillg whole cell enzyme of the Xantho-monas citri IFO 3835, cephalexin is synthesized directly from 7-amino-deacetoxy cephalosporanic acid (7-ADCA) and phenyl glycine methyl ester (PGM). To date, cephalexin has been manufactu-red by chemical process involving fairly large number of steps to protect the amino group of phenly glycine and carboxyl group of 7-ADCA. However, the enzymatic process involves only a single step with 85％ conversion in 90 minutes. The fermentation variables studied indicate that oxygen transfer is limiting step in the enzyme production. Optimum conditions for enzymatic reaction were 37 C, pH 6.0, and the optimum substrate molar ratio of PGM to 7-ADCA was 2. Other variables that are related to the biochemical properties of whole cell enzyme temperature stability, pH stability, kinetic constants, reusing effect, enzyme loading effect were also evaluated.

• Journal of Industrial Technology
• /
• v.25 no.B
• /
• pp.221-229
• /
• 2005

We present a numerical analysis of the optimal group number for minimizing the average paging delay. In the analysis, we consider uniform distributions for location probability conditions and apply M/D/1 queueing model to paging message queues of cells. We also get the lower bounds of group numbers and investigate the minimum transmission capacity under average paging delay constraints. Minimizing the average paging delay is important because it means minimizing the amount of bandwidth used for locating mobile terminals. Therefore, the numerical results of this paper will be very useful in PCS system when designing its signalling capacity due to its simplicity and effectiveness.

• Journal of Embryo Transfer
• /
• v.29 no.2
• /
• pp.101-109
• /
• 2014

Matrix Metalloproteinases (MMP)-2 and -9 are participated in embryo development, implantation, remodeling of epithelial cell and ovulation. The objective of this study is to evaluate an impact of MMP2 and MMP9 on embryonic developmental competence as well as gene expression profiles of in vitro-produced bovine embryos. After in vitro fertilization, embryos of all groups were transferred into IVC-2 medium treated with MMP2 and MMP9 to check the optimum concentration on the basis of embryo development competence and cell numbers. The optimum concentrations for MMP2 and 9 were 1,200 ng/ml and 300 ng/ml. The blastocyst development competence was not different among 1,200 ng/ml of MMP2 vs. 300 ng/ml of MMP9 vs. combined MMP2 + 9 vs. control groups ($41.46{\pm}10.66$ vs. $37.73{\pm}8.92$ vs. $45.11{\pm}11.41%$ vs. $41.59{\pm}11.88$, respectively). Furthermore, the developmental competences to hatching and hatched blastocysts were not also different among the same groups ($79.84{\pm}12.63$ vs. $83.3{\pm}17.46$ vs. $78.55{\pm}14.48%$ vs. $72.02{\pm}14.09$). In addition, total cell number was significantly (p<0.05) greater in blastocyst treated with MMP9 300 ng/ml among all treatment groups. On the other hand, there was no significant difference of ICM vs. TE ratio in all groups. The expression of five out of six genes (i.e., MMP2, MMP9, IFNt, SSLP1 and HNRNPA2B1) was different among the groups. The expression of IFNt and HNRNPA2B1 genes was significantly greater in MMP9 (p<0.05), but there was no difference of MMP9 expression between MMP2 and MMP9 group (p>0.05). The normalized expression of MMP2 and SSLP1 was greater in MMP2 than other groups (p<0.05). In conclusion, MMPs treatment during IVC-2 medium was remarkably effected on blastocyst developmental competence and gene expression profiles that are related to embryo quality and implantation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.10
• /
• pp.1510-1516
• /
• 2007

These experiments were carried out to optimize the parameters of electrical activation, methods of parthenogenetic activation and embryo culture in vitro and meanwhile to isolate embryonic stem cells-like (ESCs) derived from porcine parthenogenetic blastocysts (pPBs). These results showed that, as the electric field strength increased from 1.0 to 2.7 kV/cm, the cleavage rate of parthenogenetic embryos increased gradually but the rate of oocyte lysis was significantly increased when using 2.7 kV/cm field strength. The rate of cleavage in 2.2 and 2.7 kV/cm groups was significantly increased in comparison with that of the 1.0 kV/cm group. A voltage field strength of 2.2 kV/cm DC was used to investigate blastocyst development following activation with a single pulse of 30 or $60-{\mu}sec$ pulse duration. The optimum pulse duration was 30-${\mu}sec$, with a blastocyst rate of 20.7%. Multiple pulses were inferior to a single pulse for blastocyst yield (8.0% vs. 29.9) (p<0.05). For porcine oocyte parthenogenetic activation methods, the rates of cleavage (79.0% vs. 59.8%) and blastocysts (19.4% vs. 3.4%) were significantly increased in electrical activation in contrast to chemical activation with ionomycin/6-DMAP (p<0.05). Rates of cleavage and blastocyst formation in NCSU-23 and PZM-3 embryo media were higher than those of G1.3/G2.3 serial culture media, but there was no significant difference among the three groups. The total cell number of blastocysts in PZM-3 embryo culture media containing $5{\mu}g/ml$ insulin was significantly higher than that of the control (no insulin) ($44.3{\pm}9.1$ vs. $33.9{\pm}11.7$). For isolation of PESCs-like, the rates of porcine blastocysts attached to feeder layers and ICM colony formation in Method B (nude embryo culture) were better than those in Method A (intact embryo culture).

• Korean Journal of Plant Resources
• /
• v.26 no.2
• /
• pp.284-288
• /
• 2013

This study aimed to get the basic data on the breeding of good varieties in Hypericum patulum Thunberg. The optimum materials, concentration and soaking time were examined to identify the effective approach to induce tetraploid plant by colchicine treatment to cultivate the varieties. For the seed germination rate of seed by colchicine treatment, the higher colchicine concentration was and the longer soaking time was, the more the germination rate decreased. While individuals were germinated in 16 test groups except control group (no treatment group), all the plants were diploid and no tetraploid was induced. For the plant regeneration rate by colchicine treatment on the explant of Hypericum patulum Thunberg that was under in vitro culture, the higher the colchicine concentration increased, the ress the regeneration rate. While total 147 individuals were regenerated in all treatment, when the explant was soaking treatment in more than 0.05% for over 6 hours, tetraploid could be obtained. In the soaking treatment of 0.05% for over 6 hours, tetraploid could be obtained. In particular, for the soaking treatment in 0.05% for 12 hours, 8 tetraploids were induced, which was about 47.1% of the number of plant regenerated. In accordance with the observation on doubling of DNA contents in leaf in order to identify polyploidy, the peak DNA content of G1 phase was 94.5 for diploid and 192.5 for tetraploid. It confirmed doubling of DNA content. Furthermore, the number of chloroplasts per guard cell depending on polyploid was around 10 in diploid and 17 to 19 in tetraploid, which were around 1.7 to 1.9 times as much as diploid.