• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.89-92
• /
• 2001

Aspergillus niger has been used as a host system to express many heterologous proteins. It has various advantages over other expression systems in that it is a small eukaryotic GRAS (Generally Recognized aS Safe) organism with a capacity of secreting large amount of foreign proteins. However, it has been known that the presence of an abundant protease is a limiting factor to express a heterologous protein. The proteases deficient mutants of A. niger were obtained using UV -mutagenesis. A total of 1 ${\times}$ $10^5$ spores were irradiated with 10-20% survival dose of UV, 600J/M2 at 280nm, and the resulting spores were screened on the casein -gelatin plates. Ten putative protease deficient mutants were further analyzed on the starch plates to differentiate the pro from the secretory mutant. An endogenous extracellular enzyme, glucose oxidase, was also examined to confirm that the mutant phenotype was due to the proteases deficiency rather than the mutation in the secretory pathway. The reduced proteolytic activity was measured using SDS-fibrin zymography gel, casein degradation assay, and bio-activity of a supplemented hGM -CSF (human Granulocyte-Macrophage Colony Stimulating Factor). Comparing with the wild type strain, less than 30 % of proteolytic activity was observed in the culture filtrate of the protease deficient mutant (pro -20) without any notable changes in cell growth and secretion.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.138.2-139
• /
• 2003

Grapevine leafroll-associated 1 virus (GLRaV-1) and Grapevine leafroll-associated 3 virus (GLRaV-3), member of the genus Ampelovirus, are important viral disease of grapevine in the world. these viruses transmitted only dicotyledonous host by vectors such as mealybugs and there is no suitable herbaceous host for virus. The diseased leaves turn yellowish or reddish depending on cultivars and viruses. Viruses are existed at low concentration and ununiformly distribution in grapevine. Using small-scale double-stranded RNA (dsRNA) extraction method, reverse transcription and polymerase chain reaction (RT-PCR) product of 1Kb long which encoded of coat protein (CP) gene for both viruses was successfully amplified with a specific primers. The RT-PCR product was cloned into the plasmid vector and its nucleotide sequences were determined from selected recombinant cDNA clones. Sequence analysis revealed that the CP of GLRaV-1 consisted of 969 nucleotide, which encoded 323 amino acid residues and CP of GLRaV-3 consisted of 942 nucleotide, which encoded 314 amino acid residues. The CP of GLRaV-1 and GLRaV-3 has 93.8％ and 98.7％ amino acid sequence identities, respectively.

• Genomics & Informatics
• /
• v.12 no.3
• /
• pp.87-97
• /
• 2014

Although the number of protein-coding genes is not highly variable between plant taxa, the DNA content in their genomes is highly variable, by as much as 2,056-fold from a 1C amount of 0.0648 pg to 132.5 pg. The mean 1C-value in plants is 2.4 pg, and genome size expansion/contraction is lineage-specific in plant taxonomy. Transposable element fractions in plant genomes are also variable, as low as ~3% in small genomes and as high as ~85% in large genomes, indicating that genome size is a linear function of transposable element content. Of the 2 classes of transposable elements, the dynamics of class 1 long terminal repeat (LTR) retrotransposons is a major contributor to the 1C value differences among plants. The activity of LTR retrotransposons is under the control of epigenetic suppressing mechanisms. Also, genome-purging mechanisms have been adopted to counter-balance the genome size amplification. With a wealth of information on whole-genome sequences in plant genomes, it was revealed that several genome-purging mechanisms have been employed, depending on plant taxa. Two genera, Lilium and Fritillaria, are known to have large genomes in angiosperms. There were twice times of concerted genome size evolutions in the family Liliaceae during the divergence of the current genera in Liliaceae. In addition to the LTR retrotransposons, non-LTR retrotransposons and satellite DNAs contributed to the huge genomes in the two genera by possible failure of genome counter-balancing mechanisms.

• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.7
• /
• pp.961-967
• /
• 2018

Lao-native beef cattle are primarily Bos indicus, and most ruminant production in Laos is still dominated by small-scale or backyard producers that use traditional practices, resulting in low productivity. The cattle herd size in Laos has grown by an average of 5 percent per year from 1.52 million in 2010/11 to 1.81 million in 2014/15. In 2016, the Laos cattle population was 1.88 million head, with smallholder farmers representing 98% of production despite efforts by the Laos government to develop commercial-scale farms. There were 170 commercial cattle farms in 2016, with 56 percent in the Central region of Laos. Although, overall, ruminant meat production has tended to increase but with consumption at 7.29 kg/capita/yr in 2013, it remains insufficient to meet demand. Crop residues and agro-industrial by-products used in ruminant diets include rice straw, cassava pulp and wet brewers' grains as roughage, energy and protein sources, respectively. The Belt and Road Initiative proposed by China in 2013 will connect China closely with all countries in Southeast Asia. This initiative will change landlocked Laos to land linked for investors who will benefit from convenient transport at a lower cost, promoting agricultural production in Laos.

• BMB Reports
• /
• v.32 no.2
• /
• pp.203-209
• /
• 1999

Three-week grown Arabidopsis thaliana leaves were wounded by cutting whole leaves with a razor blade into pieces (about$3\;mm\;{\times}\;3\;mm$) submerged in various solutions, and incubated in a growth chamber for 24 h. We measured and compared activities of several enzymes such as phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), thioredoxin, thioredoxin reductase, thioltransferase, glutathione reductase, and $NADP^+$ -malate dehydrogenase. PAL activity was decreased in $HgCl_2$-, $CdCl_2$-, and glyphosate-treated leaf slices, and could not be detected after treatment with $CdCl_2$. TAL activity was found to be maximal in the $CdCl_2$-treated leaf slices. Activity of thioredoxin, a small protein known as a cofactor of ribonucleotide reductase and a regulator of photosynthesis, was significantly increased in the $CdCl_2$-treated leaf slices, while thioredoxin reductase activity was maximal in the $HgCl_2$-treated leaf slices. Thioltransferase and glutathione reductase activities were significantly decreased in the $HgCl_2$-treated leaf slices. $NADP^+$ -malate dehydrogenase activity remained relatively constant after the chemical treatments. Our results strongly indicate that sulfhydryl-related and phenylpropanoid-synthesizing enzyme activities are affected by chemical treatments such as hydrogen peroxide, heavy metals, and glyphosate.

• Applied Microscopy
• /
• v.26 no.2
• /
• pp.197-206
• /
• 1996

cis-Dichlorodiammineplatinum (II) (cis-Platin) inhibits the proliferation and growth of the tumor cells by way of inhibiting DNA and protein synthesis of the cancer cells. Although cis-Platin is very effective antitumor drug, it also produces many other side effects. Thus the author has studied the effects of cis-Platin on the proximal epiphyseal plate in the tibia of the rat. The results were as follows: In the chondrocyte of the proliferative zone, sacculated, and fragmented cisternae of rough endoplasmic reticulum, some mitochondria with disorganized mitochondrial cristae and distorted procollagens were observed, and in the matrix some large matrix granules and dispersed collagen fibrils were revealed on the 1st, 3rd day and 1st week group of cis-Platin treated rats. In the chondrocyte of the proliferative zone of cis-Platin treated rats on the 2nd and 3rd week group, parallely arranged rough endoplasmic reticulum and many procollagens were shown, and in the matrix a number of large matrix granules and many small matrical granules as well as collagen fibrils were revealed. Consequently it is suggested that though cis-Platin induces the degenerative changes of the chondrocyte resulting in components of the cartilagenous matrix, these toxic effects are regressed with time.

• Korean Journal of Food Science and Technology
• /
• v.20 no.6
• /
• pp.890-894
• /
• 1988

The baking quality of flours produced from Dark Northern Spring(DNS). Hard Red Winter(HRW) and Australian Standard White(ASW) were examined. To improve the baking quality of HRW and ASW, oxidants such as dehydroascorbic acid(DHA) and potassium bromate$(KBrO_3)$ were added. The protein content of HRW was about 3% higher than that of ASW but the specific volume of the baked gluten extracted from HRW and ASW were nearly same. By addition of DHA 100ppm and $KBrO_3$ 50ppm as oxidants to HRW and ASW, the farinogram's stability was strengthened and departure time, time to breakdown were extended. The specific volume of the bread based on HRW was very small but it was improved significantly by addition of oxidants. According to the quality scoring of bread, the breads based on DNS, HRW and ASW were 93, 72 and 75, respectively. The baking quality of HRW was improved by DHA and $KBrO_3$ but not much in ASW.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.641-644
• /
• 2005

The study on the interaction forces of some biological materials is important to understanding biological phenomena and their application to practical purpose. This paper introduces a measuring technique for biological adhesive forces using the AFM(Atomic Force Microscope). Since no standardized thesis on adhesive forces exist, the adhesive forces is defined as adhesive forces against a hardened surface of biological materials. To grant the results are meaningful, which is based on the understanding the surface characteristics of biological materials using the AFM, a nominal value of average adhesive force per unit area should be measured. Therefore the modified AFM probe with small micro glass bead was proposed so that it can guarantee the required contact area for measuring the average adhesive forces. A pyrex glass substrate with circular patterns, which was fabricated by micromachining technique, is introduced in order to controll the contact area. The two types of mussel adhesive proteins, Celltak and recombinant-MGFP5, were tested by the proposed measuring method. The test results show that the adhesive force of the mussel adhesive proteins can be reliably measured by use of this method.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.194-200
• /
• 1989

The nucleotide sequence of inducible chloramphenicol acetyl-transferase(CAT) gene isolated from a small plasmid pSBK203 of Staphylococcus aureus was determined. The base sequence shows that structural gene of pSBK203-CAT encodes a protein of 213 amino acids and has a leader region which encodes a short polypeptide of 9 amino-acids in its upstream. vertical bar /sup 35/S vertical bar-Methionine labelled CAT gene product in minicell showed almost same mobility with pC194-CAT of which molecular weight is 24Kdal on polyacrylamide gel electrophoresis. Predicted amino acid sequence of pSBK203-CAT has revealed a high degree of homology with the CATs of pC194 and pC221 than those of cat-86, Tn9 and proteus mirabilis PM13.

• BMB Reports
• /
• v.37 no.1
• /
• pp.83-92
• /
• 2004

As a result of the enormous amount of information that has been collected with E. coli over the past half century (e.g. genome sequence, mutant phenotypes, metabolic and regulatory networks, etc.), we now have detailed knowledge about gene regulation, protein activity, several hundred enzyme reactions, metabolic pathways, macromolecular machines, and regulatory interactions for this model organism. However, understanding how all these processes interact to form a living cell will require further characterization, quantification, data integration, and mathematical modeling, systems biology. No organism can rival E. coli with respect to the amount of available basic information and experimental tractability for the technologies needed for this undertaking. A focused, systematic effort to understand the E. coli cell will accelerate the development of new post-genomic technologies, including both experimental and computational tools. It will also lead to new technologies that will be applicable to other organisms, from microbes to plants, animals, and humans. E. coli is not only the best studied free-living model organism, but is also an extensively used microbe for industrial applications, especially for the production of small molecules of interest. It is an excellent representative of Gram-negative commensal bacteria. E. coli may represent a perfect model organism for systems biology that is aimed at elucidating both its free-living and commensal life-styles, which should open the door to whole-cell modeling and simulation.