• Journal of Life Science
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• v.16 no.3 s.76
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• pp.454-458
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• 2006

HSF1 is the heat shock transcription factor in Saccharomyces cerevisiae. S. cerevisiae KNU5377 can ferment at high temperature such as $40^{\b{o}}C$. We have been the subjects of intense study because Hsf1p mediates gene expression not only to heat shock, but to a variety of cellular and environmental stress challenges. Basing these facts, we firstly tried to construct the hsf1 gene-deleted mutant. PCR-method for fast production of gene disruption cassette was introduced in a thermotolerant yeast S. cerevisiae KNU5377, which allowed the addition of short flanking homology region as short as 45 bp suffice to mediate homologous recombination to kanMX module. Such a cassette is composed of linking genomic DNA of target gene to the selectable marker kanMX4 that confers geneticin (G418) resistance in yeast. That module is extensively used for PCR-based gene replacement of target gene in the laboratory strains. We describe here the generation of hsf1 gene disruption construction using PCR product of selectable marker with primers that provide homology to the hsf1 gene following separation of haploid strain in wild type yeast S. cerevisiae KNU5377. Yeast deletion overview containing replace cassette module, deletion mutant construction and strain confirmation in this study used Saccharomyces Genome Deletion Project (http:://www-sequence.standard.edu/group/yeast_deletion_project). This mutant by genetic manipulation of wild type yeast KNU5377 strain will provide a good system for analyzing the research of the molecular biology underlying their physiology and metabolic process under fermentation and improvement of their fermentative properties.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.1023-1031
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• 2017

The conformational change of cellular prion protein ($PrP^C$) to its misfolded counterpart, termed $PrP^{Sc}$, is mediated by a hypothesized cellular cofactor. This cofactor is believed to interact directly with certain amino acid residues of $PrP^C$. When these are mutated into cationic amino acid residues, $PrP^{Sc}$ formation and prion replication halt in a dominant negative (DN) manner, presumably due to strong binding of the cofactor to mutated $PrP^C$, designated as DN PrP mutants. Previous studies demonstrated that plasminogen and its kringle domains bind to PrP and accelerate $PrP^{Sc}$ generation. In this study, in vitro binding analysis of kringle domains of plasminogen to Q167R DN mutant PrP (PrPQ167R) was performed in parallel with the wild type (WT) and Q218K DN mutant PrP (PrPQ218K). The binding affinity of PrPQ167R was higher than that of WT PrP, but lower than that of PrPQ218K. Scatchard analysis further indicated that, like PrPQ218K and WT PrP, PrPQ167R interaction with plasminogen occurred at multiple sites, suggesting cooperativity in this interaction. Competitive binding analysis using $\small{L}$-lysine or $\small{L}$-arginine confirmed the increase of the specificity and binding affinity of the interaction as PrP acquired DN mutations. Circular dichroism spectroscopy demonstrated that the recombinant PrPs used in this study retained the ${\alpha}$-helix-rich structure. The ${\alpha}$-helix unfolding study revealed similar conformational stability for WT and DN-mutated PrPs. This study provides an additional piece of biochemical evidence concerning the interaction of plasminogen with DN mutant PrPs.

• Journal of Life Science
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• v.28 no.10
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• pp.1212-1219
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• 2018

The critical role of heat shock protein 90 (Hsp90) in tumorigenesis led to the development of several first- and second-generation Hsp90 inhibitors, which have demonstrated promising responses in cancers. In this study, we found second-generation Hsp90 inhibitor BIIB021-resistant multidrug-resistant (MDR) human cancer cells, although BIIB021 was shown to be active in first-generation Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG)-resistant MDR cells. MCF7-MDR and HeyA8- MDR cells were more resistant to BIIB021 than their parental counterparts, indicating that BIIB021 cannot be applicable to all cancer cells expressing MDR proteins. We revealed that dimethyl-celecoxib (DMC), one of the non-steroidal anti-inflammatory drugs (NSAIDs), potentiated cytotoxicity of BIIB021 against both BIIB021-resistant and BIIB021-sensitive MDR cells. The effectiveness of NSAIDs involving celecoxib and DMC in combination with BIIB021 led to the autophagic degradation/down-regulation of mutant p53 (mutp53) that overexpressed MDR cells and the suppression of Hsp70 induction. This resulted in sensitization of MDR cells to BIIB021. Moreover, autophagy induction by sulindac sulfide, another type of NSAID, and niclosamide, an FDA-approved anthelmintic drug, potentiated 17-AAG-mediated autophagic degradation/down-regulation of mutp53 and c-Myc, client proteins of Hsp90. Therefore, our results suggest that NSAIDs and niclosamide positively enhance the anticancer activity of Hsp90 inhibitors through an autophagic pathway. They may also be new candidates for sensitizing MDR cells to Hsp90 inhibitors.

• Plant Resources
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• v.5 no.2
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• pp.141-154
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• 2002

In this experiment, three kinds of mutations(ge, re, and eml )relating to the size of embryos were used to study their generation, genetic mechanism and developmental characteristics, and the interactions between embryo and endosperm were also examined. Giant embryo mutation comprises 7 kinds including the already isolated ge, and ge-2, which share an identical gene site. The SAM and the size of radicule for the ge showed little difference compared to a normal type. The number of embryo cells did not increased as much as it would affect the size of embryo. Therefore, the enlargement of embryo was due to the enlargement of scutellum that originated from the corpulence of each cell. Both F$_1$' s of re ]and odm 49 formed reduce embryos, and other combinations of hybridization showed all wild type of embryo sizes. Accordingly, the odm 49 must have an identical gene site of re 1, while odm 48 and odm 62 have different gene sites. Their shoots and radicules also shrank by the same ratio, however no sign of physical change was noticed. The size of embryo cell showed no change, while the number of cells was the half of that of wild types. The three gene sites of re represent all of them control the size of the entire embryo forming organs. The eml 1 was defined to have temperature sensibilities that the generation of endosperms was active at a high temperature while that was hampered at a low temperature.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.101-108
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• 2013

To develop new varieties of rapeseed (Brassica napus L.), the seeds of three varieties, 'Naehan', 'Tammi', and 'Halla' were irradiated with proton ion beams and gamma rays with 0 to 2,000 Gy. We had selected 9 lines in $M_5$ generation, and their useful characteristics were investigated by progressing from $M_6$ to $M_7$ generation for checking uniformity and stability. The 9 lines selected in $M_5$ generation were maintained their characteristics in terms of flowering date, maturing date, and plant height through $M_6$ to $M_7$ generations. Especially, 2 lines of NP600-1-1-198-2-1 and NP1000-13-2-362-4-1 selected in $M_5$ generation derived from 'Naehan' had characteristics of early maturity and shorter stem than original variety, and they also were maintained characteristic of early maturity such as 10~11 days earlier flowering date and 6~9 days earlier maturing date through $M_6$ to $M_7$ generations. For stem length, they showed characteristics of shorter stem in 2 lines of NP600-1-1-198-2-1 line and NP1000-13-2-362-4-1 line about 16%, 25% shorter stem than original variety respectively through $M_6$ to $M_7$ generations. Furthermore, some characteristics of 2 lines compared to the original variety were similar or higher in weight of 1,000 seeds, number of branches per plant, number of siliqua per panicle, number of seeds per silique, oil contents, and oleic acid contents. The line with large and plump flowers selected in $M_5$ generation also showed large and dark yellow flowers through $M_6$ to $M_7$ generations. The lines with High oleic acid and low saturated fatty acid contents selected in $M_5$ generation were maintained characteristics through $M_6$ to $M_7$ generation and these useful characteristics were expected for developing a new variety for bio diesel uses.

• Journal of Information Processing Systems
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• v.11 no.2
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• pp.280-294
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• 2015

This paper presents the infectious watermarking model (IWM) for the protection of video contents that are based on biological virus modeling by the infectious route and procedure. Our infectious watermarking is designed as a new paradigm protection for video contents, regarding the hidden watermark for video protection as an infectious virus, video content as host, and codec as contagion medium. We used pathogen, mutant, and contagion as the infectious watermark and defined the techniques of infectious watermark generation and authentication, kernel-based infectious watermarking, and content-based infectious watermarking. We experimented with our watermarking model by using existing watermarking methods as kernel-based infectious watermarking and content-based infectious watermarking medium, and verified the practical applications of our model based on these experiments.

• BMB Reports
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• v.35 no.5
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• pp.443-451
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• 2002

Malonate is a three-carbon dicarboxylic acid. It is well known as a competitive inhibitor of succinate dehydrogenase. It occurs naturally in biological systems, such as legumes and developing rat brains, which indicates that it may play an important role in symbiotic nitrogen metabolism and brain development. Recently, enzymes that are related to malonate metabolism were discovered and characterized. The genes that encode the enzymes were isolated, and the regulation of their expression was also studied. The mutant bacteria, in which the malonate-metabolizing gene was deleted, lost its primary function, symbiosis, between Rhizobium leguminosarium bv trifolii and clover. This suggests that malonate metabolism is essential in symbiotic nitrogen metabolism, at least in clover nodules. In addition to these, the genes matB and matC have been successfully used for generation of the industrial strain of Streptomyces for the production of antibiotics.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.375-383
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• 2008

It is well known that NtMEK2, a tobacco MAPK kinase, is the upstream kinase of both salicylic acid-induced protein kinase and wound-induced protein kinase. In addition, expression of $NtMEK2^{DD}$, a constitutively active mutant of NtMEK2, is known to induce multiple defense responses in tobacco. In this study, transgenic rice plants that contained an active or inactive mutant of NtMEK2 under the control of a steroid inducible promoter were generated and used to determine if a similar MAPK cascade is involved in disease resistance in rice. The expression of $NtMEK2^{DD}$ in transgenic rice plants resulted in HR-like cell death. The observed cell death was preceded by the activation of endogenous rice 48-kDa MBP kinase, which is also activated by Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice. In addition, prolonged activation of the MAPK induced the generation of hydrogen peroxide and up-regulated the expression of defense-related genes including the pathogenesis-related genes, peroxidases and glutathione S-transferases. These results demonstrate that NtMEK2 is functionally replaceable with rice MAPK kinase in inducing the activation of the downstream MAPK, which in turn induces multiple defense responses in rice.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1773-1777
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• 2002

Reactive oxygen species(ROS) have been investigated to have pivotal roles on amyloidogenecity of $\beta-amyloidpeptide(A\beta)$, the major component of senile plaques in Alzheimer's disease(AD) brain. Addition of radical scavengers is one of the on-going strategies for therapeutic treatment for AD patients. Hsp104 protein including two ATP binding sites from Saccharomyces cerevisiae, as a molecular chaperone, was known to function as a protector of ROS generation when exposed to oxidative stress in our previous study. This observation has led us to investigate Hsp104 protein as a molecular mediator of $A{\beta}$ aggregation in this study. We have developed a new way of expression for Hsp104 protein using GST-fusion tag. As we expected, formation of $A{\beta}$ aggregate was protected by wild type Hsp104 protein, but not by the two ATP-binding site mutant, based on Thioflavin-T fluorescence. Interestingly, Hsp104 protein was observed to keep $A{\beta}$ from forming aggregates independent of ATP binding. On the other hand, disaggregation of $A{\beta}$ aggregates by wild type Hsp104 was totally dependent on the presence of ATP. On the other hand, mutant Hsp104 with two ATP binding sites altered exhibited no inhibition. Another effective antioxidant, hydrazine analogs of curcumin were also effective in $A{\beta}$ fibrilization as protectors against oxidative stress. Based on these observations we conclude that Hsp104 and curcumin derivatives, as protectors of oxidative stress, inhibit $A{\beta}$ aggregation in virto and can be candidates for therapeutic approaches in cure of some neurodegenerative disease.

• International Journal of Industrial Entomology and Biomaterials
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• v.43 no.1
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• pp.29-36
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• 2021

Silkworms have long been bred with human history to produce silk. It has been with humans for longer than other industrial insects, and the silkworm variety has been continuously improved. Silkworms have been developed into the optimal form for producing high quality silk and pupae. Recently, the production of transgenic silkworms has further expanded the possibility of industrial value of silkworms. Kynurenine 3-monooxygenase (KMO), which is a flavin enzyme, is known for its involvement in ommochrome pigment synthesis. In the field of mammals, including humans, previous studies have revealed the function and role of KMO, which is an important enzyme for various immune responses and cell protection. However, in the case of insects, the function of KMO has only been studied to be involved in the formation of pigment, and accordingly, KMO is used exclusively on screening for generation of transgenic insects as a marker. In this study, using KMO-edited silkworms, it was intended to discover the novel functions and roles of KMO in silkworms by identifying changes in the expression of various genes associated with stress and growth. The changes were observed in expressions of genes regulating on stresses to survive and those on ecdysteroid hormone between wild-type (WT) silkworms and kmo mutant silkworms. The loss of KMO, in particular, decreased the expression of the shadow (sad) gene, one of the Halloween genes in the synthesis of ecdysteroid. In conclusion, these results suggest that silkworm KMO is responsible for potential functions regarding stress response and ecdysteroid synthesis.