• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.394-400
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• 1990

Maximization of productivity of recombinant cell fermentations requires consideration of the inverse relationship between the host cell growth rate and product formation rate. The problem of maximizing a weighted performance index was solved by using optimal control theory for recombinant E. coli fermentation. Concentration of a growth inhibitor was used as a control variable to manipulate the specific growth rate, and consequently the cloned-gene expression rate. Using a simple unstructured model to describe the main characteristics of this system, theoretical analysis showed that the optimal control profile results in an initial high growth rate phase followed by a low growth rate and high product formation rate phase. Numerical calculations were done to determine optimal switching times from the growth to the production stage for two representative cases corresponding to different dependency of the product formation rate on the growth rate. For the case when product formation rate is sensitive to the specific growth rate, the optimized operation yields about 60% increase in the final product concentration compared with a simple batch fermentation.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.51-61
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• 2010

Purpose : Previous studies have suggested that Chemokine (C-C motif) ligand-2 (CCL-2; also known as MCP-1) and CCL-5 (also known as RANTES) are possibly associated with the pathogenesis of various inflammatory and non-inflammatory renal diseases. The present study was conducted to investigate association of polymorphisms of CCL-2 and CCL-5 genes with childhood IgA nephropathy (IgAN). Methods : The authors analyzed six single nucleotide polymorphisms (SNPs) of CCL-2 and CCL-5 in 196 pediatric IgAN patients and in 285 healthy controls. We compared variations in SNPs between two several sets of IgAN subgroups, allocated by presence of proteinuria (>4 mg/$m^2$/hour), podocyte foot process effacement, and pathologically advanced disease markers, such as interstitial fibrosis, tubular atrophy, or global sclerosis. Results : Genotypic data of IgAN patients and controls showed no significant SNP frequency difference in both of of CCL-2 and CCL-5. Even though two linkage disequilibrium blocks were formed, there was no significance in the haplotype analysis. In the patient subgroup analysis, no SNP of CCL-2 and CCL-5 was found to be associated with the presence of proteinuria, podocyte foot process effacement, and pathologically advanced disease markers. Conclusion : Our data indicate that no association exists between CCL-2 and CCL-5 SNPs and childhood IgAN susceptibility, and presence of proteinuria, podocyte foot process effacement, and pathologic progression of IgAN.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.352-359
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• 2022

Recently, with the development of genetic technology, interest in environmental DNA (eDNA) to study biodiversity according to molecular biological approaches is increasing. Environmental DNA has many advantages over traditional research methods for biological communities distributed in the environment but highly depends on the established base sequence database. This study conducted a comprehensive analysis of the habitat status and classification at the genus level, which is mainly used in eDNA (12S rRNA, 16S rRNA, 18S rRNA, COI, and CYTB), focusing on Korean registration taxon groups (phytoplankton, zooplankton, macroinvertebrates, and fish). As a result, phytoplankton and zooplankton showed the highest taxa proportion in 18S rRNA, and macroinvertebrates observed the highest ratio in the nucleotide sequence database in COI. In fish, all genes except 18S rRNA showed a high taxon ratio. Based on the Korean registration taxon group, the gene construction of the top 20 genera according to bio density observed that most of the phytoplankton were registered in 18S rRNA, and the most significant number of COI nucleotide sequences were established in macroinvertebrates. In addition, it was confirmed that there is a nucleotide sequence for the top 20 genera in 12S rRNA, 16S rRNA, and CYTB in fish. These results provided comprehensive information on the genes suitable for eDNA research for each taxon group.

• Journal of Apiculture
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• v.34 no.1
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• pp.27-37
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• 2019

Rapid detection of Tropilaelaps, an external parasite of honeybees that lead to malformation of honeybee or colony collapse disorder, is becoming important. But it is very difficult to find with the naked eye of Tropilaelaps. In this study, we have developed a method to detect the specific gene of Tropilaelaps from the hive debris and to know the number of Tropilaelaps in the hive through Tropilaelaps-specific quantitative detection. Tropilaelaps-specific gene amplified in DNA extracted from hive debris by consecutive PCR (1st detection, 2nd nested PCR). It could detect 101 molecules level of Tropilaelaps-specific gene and confirm the amplification of the Tropilaelaps-specific gene. It was possible to accurately quantify the number of Tropilaelaps from the hive debris sample, which is difficult to discriminate the presence of Tropilaelaps visually, through Tropilaelaps-specific detection. Under the microscope, Tropilaelaps was collected and quantitative detection of Tropilaelaps-specific genes was performed. It was possible to quantify the number of Tropilaelaps present in the hive through the molecules of the quantified Tropilaelaps-specific genes. We suggest that hive debris can represent as a micro-environment to hive and show that it can be a simpler and more accurate sample than using a parasitic host honeybee. We expect that hive debris should facilitate the monitoring of Tropilaelaps in hive.

• The Korean Journal of Mycology
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• v.14 no.1
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• pp.9-15
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• 1986

Interspecific hybrids of Pleurotus ostreatus and Pleurotus florida were formed by using protoplasts of complementing auxotrophs. The genetic markers were shown to segregate and recombine in the first generation of monosporus isolates from basidiocarp of seven fusion products. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis. In all the crosses there was no evidence of linkage between the genetic markers. Clamp connections were formed in monosporus mycelia from basidiocarp of fusion products.

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.279-285
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• 1993

Alterations of the p53 gene arc among the most frequent genetic changes in human cancer and often result in increased levels of p53 protein within the malignant cells. Detection of accumulated p53 protein can be a useful prognostic tool in human cancer. In order to make polyclonal antibodies for immunohistochemical screening. human p53 gene was expressed in E. coli in the form of GST (glutathione S-transfi.:rase) fusion proteins. Two p53 gene fragments. which were N('()I small fragment encoding amino acid residues of 1-151-: and Ncol large fragment of 159-393. were subeloned into the unique BamHI site present within the pGEX-2T vector using BamHI linker and recombinant plasmids pGTNS and pGTNL were constructed. respectively. The p53 cDNA fragment (from pC53-$SN_3$,) encoding amino acid 38-145 (proline at residue 72) was amplified by polymerase chain reaction(PCR). The amplified DNA was digested with BamHI and Prull and inserted into the BamHI-Smal sites of pG EX-2T and recombinant plasmid pGTBP was constructed. After IPTG induction of these plasmids for 4 hours. fusion proteins were purified from E. coli extracts with glutathione Sepharose beads. The bound proteins were resolved by 10% SDS-polyacrylamide gel electrophoresis and the molecular weights were 54 kDa. 53 kDa and 40 kDa. respectively. Approximately one milligram of fusion proteins were purified from 1 -liter cultures.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.4
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• pp.81-86
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• 2003

Current growth of VLSI design depends critically on the research and development of automatic layout tool. Automatic layout is composed of placement assigning a specific shape to a block and arranging the block on the layout surface and routing finding the interconnection of all the nets. Algorithms performing placement and routing impact on performance and area of VLSI design. Switchbox routing is a problem interconnecting each terminals on all four sides of the region, unlike channel routing. In this paper we propose a genetic algorithm searching solution space for switchbox routing problem. We compare the performance of proposed genetic algorithm(GA) for switchbox routing with that of other switchbox routing algorithm by analyzing the results of each implementation. Consequently experimental results show that out proposed algorithm reduce routing length and number of the via over the other switchbox routing algorithms.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.71-75
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• 2002

We propose a new method to deal with the optimized auto-tuning for the PID controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nichols method and deciding binary strings of parents generation using by the fitness values of genetic algorithms, we perform selection, crossover and mutation to generate the descendant generation. The advantage of this method is better than the Ziegler-Nickels method in characteristic of output, and has extent of applying without limit of K, L, T parameters.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.81-89
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• 1993

In order to isolate a mutant which was constitutively expressed in xylA gene, Pxyl-cat-xylA fusion gene was constructed by the insertion of cat gene between xylA promoter and xylA structural gene in pEX13 contained xylA gene. The expression of cat and xylA gene from transformants of xylA mutant DH77 with plasmid pEXC131 containing Pxyl-cat-xylA fusion gene was induced by the addition of 0.4% xylose to media. This results indicated that cat and xylA gene were expressed under control of xylA promoter the presence of xylR gene. We have also isolated constitutive mutant plasmid pEXC131-39 from pEXC131 by trementment with N-methyl-N'-nitro-N-nitrosoguanidine(NTG). cat and xylA gene from pEXC131-39 were constitutively expressed without induction of xylose regardless of xylR gene. Transformants of xylR mutant DH60 with pEXC131-39 also expressed chloramphenicol resistances and xylose isomerase without induction of xylose. This result shows that mutation in region of xylA promoter might make it possible to be constitutively expressed.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.37-44
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• 1991

- I aimed to isolate trans-acting factors involved in the basal expression level of eukaryotic genes. One of the yeast histidine biosynthetic gene, HIS5 was taken as a model for this study. HIS5 gene has a substantial basal level in amino acid rich medium and is derepressed if starved for any single amino acid. The derepression is mediated by cis-acting DNA sequences 5'-TGACTC-3' found in 5' non-transcribed region of the gene and trans-acting factors including GCN4 as positive factor and its negative factor GCDI 7, and GCNZ as a negative factor of GCD17. I first investigated the role of these trans-acting factors in HIS5 basal expression level by using HIS5-pH05 fusion in which expression of pH05 gene encoding inorganic phosphate-repressible acid phosphatase (APase) is regulated by HIS5 promoter. Strain with gcn2 or gcn4 mutation showed 3 to 4 fold lower APase activity than wild type. The level of APase activity was similar in gcn2 and gcn4 mutants. Trans-acting factors involved in basal level were identified by isolating 14 mutants showing increased expression of HISSPH05 fusion from gcn4 background. All the mutants carry a single nuclear recessive mutation and fall into four complementation groups, designated as bell (basal expression level), be12, be23 and be14.