• Microbiology and Biotechnology Letters
• /
• v.25 no.4
• /
• pp.408-413
• /
• 1997

It was studied in order to improve the yield of serrapeptase production in fermentation that organic nitrogen sources play important roles not only as inducer, repressor and activator, but also nitrogen sources. From the investigation of the effect of Na-caseinate on the induction of serrapeptase production, it was elucidated that real inducer was leucine and strong repressor was cysteine, which were produced through hydrolysis of proteins. Serrapeptase production was strongly induced by Na-caseinate in culture time 12 hrs, but was weakly induced before and after that time. Therefore fed batch culture where partial amount of Na-caseinate is added in 12 hrs, is better than batch culture where total amount of Na-caseinate is added at the beginning. Cysteine, methionine, MgSO$_{4}$, and so on, sulfur-containing materials, repressed the serrapeptase production. In the addition of mineral salts, chlorinated salts is better than sulfated salts because of sulfur repression. The synergic effect of soybean meal with Na-caseinate on the serrapeptase production resulted from Mn$^{2+}$ contained in soybean meal, of which the optimal concentration is 4 mM in enzyme production.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.5
• /
• pp.70-75
• /
• 1999

Adaptive control in the robotic GMA(Gas Metal Arc) welding is employed to monitor the information about weld characteristics and process paramters as well as modification of those parameters to hold weld quality within the acceptable limits. Typical characteristics are the bead geometry composition micrrostructure appearance and process parameters which govern the quality of the final weld. The main objectives of this paper are to realize the mapping characteristicso f penetration through the learning. After learning the neural network can predict the pene-traition desired from the learning mapping characteristic. The design parameters of the neural network estimator(the number of hidden layers and the number of nodes in a layer) were chosen from an error analysis. partial-penetration single-pass bead-on-plate welds were fabricated in 12mm mild steel plates in order to verify the performance of the neural network estimator. The experimental results show that the proposed neural network estimator can predict the penetration with reasonable accuracy and gurarantee the uniform weld quality.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.3
• /
• pp.434-442
• /
• 2008

We observed that an inclusion body (IB) of recombinant ${\beta}$-galactosidase that was produced by the araBAD promoter system in Escherichia coli (E. coil) showed enzyme activity. In order to improve its activity, the lowering of the transcription rate of the ${\beta}$-galactosidase structural gene was attempted through competition between an inducer (L-arabinose) and an inducer analog (D-fucose). In the deep-well microtiter plate culture and lab-scale fermentor culture, it was demonstrated that the addition of D-fucose caused an improvement in specific ${\beta}$-galactosidase production, although ${\beta}$-galactosidase was produced as an IB. In particular, the addition of D-fucose after induction led to an increase in the specific activity of ${\beta}$-galactosidase IB. Finally, we confirmed that the addition of D-fucose after induction caused changes in the structure of ${\beta}$-galactosidase IB, with higher enzyme activity. Based on these results, we expect that an improved enzyme IB will be used as a biocatalyst of the enzyme bioprocess, because an enzyme IB can be purified easily and has physical durability.

• The Journal of Internal Korean Medicine
• /
• v.16 no.1
• /
• pp.181-196
• /
• 1995

The present experiments were designed to investigate the effects of BangPoongSan on the cardiovascular system in the experimental Animals. And thus the change of blood pressure, auricular blood flow, artery contraction, death rate, platelet aggregation repression, plasma coagulation factor activity, plasma antithrombin activity, whole blood viscosity and plasma viscosity were studied. The result were summarized as the followings: 1. BangPoongSan dropped the blood pressure in the spontaneous hypertensive rat. 2. The drug increased the auricular blood flow in rabbit. 3. The drug relaxed the artery contraction by pretreated norepinephrine in white rat. 4. The drug inhibited the death rate of mouse which was led to thromboembolism by serotonin and collagen. 5. The drug inhibited the platelet aggregation in rat. 6. The drug prolonged the prothrombin time and activated partial thromboplastin time on the test of plasma coagulation factor activity in rat, but was not valuable. 7. The drug presented the antithrombin activity in rat. 8. The drug reduced the whole blood viscosity and plasma viscosity in rat, but the latter was not valuable. According to the results, Bangpoongsan increased the blood flow and dropped the blood pressure by dilatation of blood vessel smooth muscle. And the drug presented the antithrombin acivity, inhibited the platelet aggregation and reduced blood viscosity. Therefore these effects are assumed to improve the cardiovascular circulation disorder and prevent thrombosis.

• Journal of Microbiology and Biotechnology
• /
• v.3 no.3
• /
• pp.146-155
• /
• 1993

A DNA fragment from an alkali-tolerent Bacillus sp., conferring strong promoter activity, was subcloned into the promoter probe plasmid pPL703 and the nucleotide sequence of this promoter region was determined. The sequence analysis suggested that this highly efficient promoter region containing the complex clustered promoters comprised three kinds of promoters (P1, P2 and P3), which are transcribed by $\sigma^B (formerly \sigma^{37}), \sigma^E(formerly \sigma^{29}) and \sigma^A (formerly \sigma^{43})$ RNA polymerase holoenzymes which play major rules at the onset of endospore formation, during sporulation and at the vegetative phase of growth, respectively. S1 nuclease mapping experiments showed that all three promoters had staggered transcription initiation points. The results of chloramphenicol acetyltransferase assay after the subcloning experiments also indicated that the expression of these clustered promoters was correlated with the programs of growth and endospore development. Promoter P1, P2 and P3 were preceded by 75% AT, 79% AT and 81% AT regions, respectively, and a partial deletion of AT-rich region prevented transcription from promoter P1 in vivo. Two sets of 5 -AGTGTT-3 sequences and inverted repeat sequences located around the promoter P1 were speculated as the possible cis acting sites for the catabolite repression in B. subtilis. In vivo transcripts from these sequence regions may be able to form a secondary structure, however, the possibility that a regulatory protein induced by the excess amount of glucose could be bound to such a domain for crucial action remains to be determined.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.11
• /
• pp.1898-1903
• /
• 2007

We attempted to modulate the overall protein expression rate through the addition of a repressor against the araBAD promoter system of Escherichia coli, in which glucose was used as a repressor. Therefore, 0.5% L-arabinose was initially contained as an inducer in culture medium, and either 2% glucose or 2% glycerol was used as a carbon source, and it was found that the expression of recombinant interferon-${\alpha}$ could be observed at the beginning of the batch culture when glycerol was used as a carbon source. However, when glucose was used, the initiation of recombinant interferon-${\alpha}$ expression was delayed compared with that when glycerol was used. Furthermore, when the addition of 0.5% glucose was carried out once or twice after 0.5% L-arabinose induction during DO-stat fed-batch culture, the distributions of soluble and insoluble recombinant interferon-${\alpha}$ were modulated. When glucose was not added after the induction of L-arabinose, all of the expressed recombinant interferon-${\alpha}$ formed an inclusion body during the later half of culturing. However, when glucose was added after induction, the expressed recombinant interferon-${\alpha}$ did not all form an inclusion body, and about half of the total recombinant interferon-${\alpha}$ was expressed in a soluble form. It was deduced that the addition of glucose after the induction of L-arabinose might lower the cAMP level, and thus, CAP (catabolite activator protein) might not be activated. The transcription rate of recombinant interferon-${\alpha}$ in the araBAD promoter system might be delayed by the partial repression. This inhibition of the transcription rate probably resulted in more soluble interferon-${\alpha}$ expression caused by the reduction of the protein synthesis rate.

• BMB Reports
• /
• v.43 no.6
• /
• pp.432-437
• /
• 2010

LBH is a transcription factor as a candidate gene for CHD associated with partial trisomy 2p syndrome. To identify potential LBH-interacting partners, a yeast two-hybrid screen using LBH as a bait was performed with a human heart cDNA library. One of the clones identified encodes ${\alpha}B$-crystallin. Co-immunoprecipitation and GST pull-down assays showed that LBH interacts with ${\alpha}B$-crystallin, which is further confirmed by mammalian two-hybrid assays. Co-localization analysis showed that in COS-7 cells, ${\alpha}B$-crystallin that is cytoplasmic alone, accumulates partialy in the nucleus when co-transfected with LBH. Transient transfection assays indicated that overexpression of LBH or ${\alpha}B$-crystallin reduced the transcriptional activities of p53 and p21, respectively, Overexpression of both ${\alpha}B$-crystallin and LBH together resulted in a stronger repression of the transcriptional activities of p21 and p53. These results showed that the interaction of LBH and ${\alpha}B$-crystallin may inhibit synergistically the transcriptional regulation of p53 and p21.