• The Korean Journal of Zoology
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• v.8 no.2
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• pp.33-36
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• 1965

We have carried out a study on the modification of the frequency of X-ray induced lethal and slow growing mutations by colchincine treatment before and after X-ray irradiation in Paramecium aurelia. 1. Lethal and slow-growing mutation induced by X-ray in Paramecium aurelia were reduced by colchicine treatment. 2. The effects of colchicine on the X-ray induced mutations were remarkable in the radiosensitive stages of cell division. 3. The pre-irradiation treatment with colchicine showed no significant influence on the frequency of mutations. 4. It is believed that the reduction of mutation induced by X-ray after treatment with colchicine was due to the fact that the delay of the cell division allowed more time for the pre-mutational damage to recover.

• YAKHAK HOEJI
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• v.32 no.6
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• pp.420-427
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• 1988

Post-translational modification of protein amino acid residues is a well known metabolic phenomenon. One such side chain modification, protein methylation, occur ubiquitously in nature, in organism ranging from prokaryotic to eukaryotic and the biological significance of protein methylation has begun to emerge. The observation that cytochrome C methylation facilitates the binding of this hemoprotein to mitochondria could be placed as the one of the examples along this line. However, the detail biological meaning of cytochrome C methylation is remained to be clarified. In the aspect of such reason this research was done. The results of this experiment were; 1) pure Euglena gracilis cytochrome C552 was isolated, 2) methylarginine and methylmethionine were not found in cytochrome C552 sequence, 3) however, Unknown Peak at 20.78min of retention time was found, and 4) this Unknown Peak was found only from Euglena cytochrome C552, so far.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.330.1-330.1
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• 2002

Arginine methylation is a common post-translation protein modification in eukaryotic cells. Protein-arginine N-methyltransferase transfer methyl groups from S-adenosyl-L-methionine to the guanidino group of arginine residues. However. The significant of this modification has been questionable. because it occurs rarely and is present at very low abundance. Recently, the discovery of two protein arginine methyltransferase, PRMT1 and CARM1, as cofactors required for responses to muclear Hormone receptors provided an indicationthat arginine methylationhave an important role in transcriptional regulation. (omitted)

• BMB Reports
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• v.54 no.11
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• pp.541-544
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• 2021

Protein glycosylation is a common post-translational modification found in all living organisms. This modification in bacterial pathogens plays a pivotal role in their infectious processes including pathogenicity, immune evasion, and host-pathogen interactions. Importantly, many key proteins of host immune systems are also glycosylated and bacterial pathogens can notably modulate glycosylation of these host proteins to facilitate pathogenesis through the induction of abnormal host protein activity and abundance. In recent years, interest in studying the regulation of host protein glycosylation caused by bacterial pathogens is increasing to fully understand bacterial pathogenesis. In this review, we focus on how bacterial pathogens regulate remodeling of host glycoproteins during infections to promote the pathogenesis.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.933-943
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• 2021

Objective : Percutaneous pedicle screw (PPS) fixation is a needle based procedure that requires fluoroscopic image guidance. Consequently, radiation exposure is inevitable for patients, surgeons, and operation room staff. We hypothesize that reducing the production of radiation emission will result in reduced radiation exposure for everyone in the operation room. Research was performed to evaluate reduction of radiation exposure by modifying imaging manner and mode of radiation source. Methods : A total of 170 patients (680 screws) who underwent fusion surgery with PPS fixation from September 2019 to March 2020 were analyzed in this study. Personal dosimeters (Polimaster Ltd.) were worn at the collar outside a lead apron to measure radiation exposure. Patients were assigned to four groups based on imaging manner of fluoroscopy and radiation modification (pulse mode with reduced dose) : continuous use without radiation modification (group 1, n=34), intermittent use without radiation modification (group 2, n=54), continuous use with radiation modification (group 3, n=26), and intermittent use with radiation modification (group 4, n=56). Post hoc Tukey Honest significant difference test was used for individual comparisons of radiation exposure/screw and fluoroscopic time/screw. Results : The average radiation exposure/screw was 71.45±45.75 µSv/screw for group 1, 18.77±11.51 µSv/screw for group 2, 19.58±7.00 µSv/screw for group 3, and 4.26±2.89 µSv/screw for group 4. By changing imaging manner from continuous multiple shot to intermittent single shot, 73.7% radiation reduction was achieved in the no radiation modification groups (groups 1, 2), and 78.2% radiation reduction was achieved in the radiation modification groups (groups 3, 4). Radiation source modification from continuous mode with standard dose to pulse mode with reduced dose resulted in 72.6% radiation reduction in continuous imaging groups (groups 1, 3) and 77.3% radiation reduction in intermittent imaging groups (groups 2, 4). The average radiation exposure/screw was reduced 94.1% by changing imaging manner and modifying radiation source from continuous imaging with standard fluoroscopy setting (group 1) to intermittent imaging with modified fluoroscopy setting (group 4). A total of 680 screws were reviewed postoperatively, and 99.3% (675) were evaluated as pedicle breach grade 0 (<2 mm). Conclusion : The average radiation exposure/screw for a spinal surgeon can be reduced 94.1% by changing imaging manner and modifying radiation source from real-time imaging with standard dose to intermittent imaging with modified dose. These modifications can be instantly applied to any procedure using fluoroscopic guidance and may reduce the overall radiation exposure of spine surgeons.

• The Journal of Korean Association of Computer Education
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• v.13 no.6
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• pp.91-98
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• 2010

NAC(Network Access Control) has been developed as a solution for the security of end-point user, to be a target computer of worm attack which does not use security patch of OS and install Anti-Virus, which spreads the viruses in the Intra-net. Currently the NAC products in market have a sufficient technology of pre-connect, but insufficient one of post-connect which detects the threats after the connect through regular authentication. Therefore NAC users have been suffered from Zero-day attacks and malware infection. In this paper, to solve the problems in the post-connect step we generate the normal behavior profiles using the traffic information of each host, host information through agent, information of open port and network configuration modification through network scanner addition to authentication of host and inspection of policy violation used before. Based on these we propose the system to detect the hosts infected malware.

• Journal of Life Science
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• v.26 no.3
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• pp.364-375
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• 2016

Post-translational modification is an efficient process to rapidly transduce external stimulus into cellular response. Ubiquitination is a typical post-translational modification which is a highly conserved process in eukaryotes. UPS (Ubiquitin/Proteasome System) mediated by the ubiquitination is to target diverse cellular proteins for degradation. Among E3 ubiquitin ligases that function as the key determinant for substrate recognition, CRL (cullin–RING E3 ubiquitin ligase) is the largest family and forms the complex composed of cullin, RBX1, adaptor and substrate receptor. Although CRL1, also known as SCF complex, has been widely researched for its biological role, the functional studies of CRL4 have been relatively elusive. In Arabidopsis, there are 119 substrate receptors named DCAF (DDB1 CUL4 Associated Factor) proteins for CRL4 and a fraction of DCAF proteins have been identified for their potential functions so far. In this paper, current understanding on structure and biological roles of plant CRL4 complexes in a diverse of cellular events is reviewed, especially focusing on CRL4 substrate receptors. Moreover, the regulatory mechanism of CRL4’s activity is also introduced. These studies will be helpful to further understand the signal transduction pathways in which such CRL4 complexes are involved and give a clue to establish the action network of entire CRL4 complexes in plants.

• Journal of Life Science
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• v.24 no.2
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• pp.196-208
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• 2014

During the life cycle of plants, water deficit leads to an adverse effect on its growth and development. To increase the productivity of crops, overcoming such drought stress is one of the most important issues in the field of plant study. Among plant hormones, the phytohormone, abscisic acid (ABA) plays a crucial role in eliciting resistance to drought stress as well as in multiple developmental processes, such as seed germination, stomatal closure, and seedling growth. Therefore, further understanding of the ABA-mediated signal transduction pathway in plants is an effective strategy to generate drought-tolerant plants. Posttranslational modification, such as phosphorylation and ubiquitination, is an efficient mechanism for plants to acquire quick adaptation against environmental stress conditions since this process directly affects pre-existing signaling components by modulating protein activity and stability. Here, recent reports on ABA signaling are reviewed, especially focusing on ABA transport, perception, signaling, and posttranslational modification in ABA-mediated cellular responses. Also, we present future prospects on how the control of such a mechanism can be applied to generate useful agricultural crops.

• KSBB Journal
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• v.16 no.5
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• pp.435-441
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• 2001

In spite of the powerfulness for the simultaneous study of proteome expression and post-translational modification, 2-D PAGE has inevitable limitation on detect low aboundant proteins. Since many of the low abundant proteins are likely to have very important regulatiory functions in cells, separation and analysis of low copy number proteins is an important issue in proteome studies and challenge for 2-D techniques. Among various methods developed to detect low abundant proteins, electrophoretic protein prefractionation, chromatographic protein prefractionation, and subcellular fractionation are explained in this paper. Their practical strengths and weaknesses are also explained with current research trends.

• Genomics & Informatics
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• v.9 no.3
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• pp.136-137
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• 2011

Methylation of cytosine is a post-synthesis modification that does not affect the primary DNA sequence but greatly influences gene expression level and phenotypes of an organism. As high-throughput sequencing of bisulfite-treated DNA is the most efficient method to identify methylated sites, several tools to map sequencing reads on a reference are available. But tools to visualize and to interpret the methylation level of methylation sites are currently insufficient. Herein, we present a novel tool to visualize the methylation level of CpG sites.