• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.80.2-80.2
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• 2007

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• Molecules and Cells
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• v.43 no.4
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• pp.331-339
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• 2020

Genetic modifications in noncoding regulatory regions are likely critical to human evolution. Human-accelerated noncoding elements are highly conserved noncoding regions among vertebrates but have large differences across humans, which implies human-specific regulatory potential. In this study, we found that human-accelerated noncoding elements were frequently coupled with DNase I hypersensitive sites (DHSs), together with monomethylated and trimethylated histone H3 lysine 4, which are active regulatory markers. This coupling was particularly pronounced in fetal brains relative to adult brains, non-brain fetal tissues, and embryonic stem cells. However, fetal brain DHSs were also specifically enriched in deeply conserved sequences, implying coexistence of universal maintenance and human-specific fitness in human brain development. We assessed whether this coexisting pattern was a general one by quantitatively measuring evolutionary rates of DHSs. As a result, fetal brain DHSs showed a mixed but distinct signature of regional conservation and outlier point acceleration as compared to other DHSs. This finding suggests that brain developmental sequences are selectively constrained in general, whereas specific nucleotides are under positive selection or constraint relaxation simultaneously. Hence, we hypothesize that human- or primate-specific changes to universally conserved regulatory codes of brain development may drive the accelerated, and most likely adaptive, evolution of the regulatory network of the human brain.

• BioChip Journal
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• v.12 no.4
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• pp.280-286
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• 2018

Hydrogel scaffolds composed of multiple components are promising platform in tissue engineering as a transplantation materials or artificial organs. Here, we present a new fabrication method for implementing multi-layered macroscopic hydrogel scaffold composed of multiple components by controlling height of hydrogel layer through precise control of ultraviolet (UV) energy density. Through the repetition of the photolithography process with energy control, we can form several layers of hydrogel with different height. We characterized UV energy-dependent profiles with single-layered PEGDA posts photocrosslinked by the modular methodology and examined the optical effect on the fabrication of multi-layered, macroscopic hydrogel structure. Finally, we successfully demonstrated the potential applicability of our approach by fabricating various macroscopic hydrogel constructs composed of multiple hydrogel layers.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.1-13
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• 2010

There are a great numbers of disabled individuals who cannot freely move or control specific parts of their body because of serious neurological diseases such as spinal cord injury, amyotrophic lateral sclerosis, brainstem stroke, and so on. Brain-computer interfaces (BCIs) can help them to drive and control external devices using only their brain activity, without the need for physical body movements. Over the past 30 years, several Bel research programs have arisen and tried to develop new communication and control technology for those who are completely paralyzed. Thanks to the rapid development of computer science and neuroimaging technology, new understandings of brain functions, and most importantly many researchers' efforts, Bel is now becoming 'practical' to some extent. The present review article summarizes the current state of electroencephalogram (EEG)-based Bel, which have been being studied most widely, with specific emphasis on its basic concepts, system developments, and prospects for the future.

• BMB Reports
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• v.53 no.11
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• pp.551-564
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• 2020

Proper development of the nervous system is critical for its function, and deficits in neural development have been implicated in many brain disorders. A precise and predictable developmental schedule requires highly coordinated gene expression programs that orchestrate the dynamics of the developing brain. Especially, recent discoveries have been showing that various mRNA chemical modifications can affect RNA metabolism including decay, transport, splicing, and translation in cell type- and tissue-specific manner, leading to the emergence of the field of epitranscriptomics. Moreover, accumulating evidences showed that certain types of RNA modifications are predominantly found in the developing brain and their dysregulation disrupts not only the developmental processes, but also neuronal activities, suggesting that epitranscriptomic mechanisms play critical post-transcriptional regulatory roles in development of the brain and etiology of brain disorders. Here, we review recent advances in our understanding of molecular regulation on transcriptome plasticity by RNA modifications in neurodevelopment and how alterations in these RNA regulatory programs lead to human brain disorders.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.94-99
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• 2006

The tadpole larvae of most ascidians have two sensory pigment cells in their brain vesicle. The anterior otolith pigment cell is sensitive to gravity, whereas the posterior ocellus pigment cell responds to light. Besides these two sensory cells, the larvae also possess another type of sensory receptor cell: hydrostatic pressure receptor (Hpr) cells. The Hpr cells have been presumed to sense hydrostatic water pressure, although no functional analysis has been performed. In larvae of the ascidian Halocynthia reretzi, the development of the Hpr cells and their structure in the brain vesicle are poorly understood. To investigate the morphology and formation of the Hpr cells, we established a monoclonal antibody, Hpr-1, that specifically recognizes Hpr cells. The Hpr-1 antigens became detectable in the brain vesicle at the late tailbud stage. Each Hpr cell projected a small globular body, connected by a short stalk, into the lumen of the brain vesicle. The brain vesicle showed remarkable left-right asymmetry. Pigment cells were located on the right side in the lumen of the brain vesicle, whereas Hpr cells were present in the left side. After metamorphosis, the Hpr cells were observed near the rudimental siphons of the juvenile.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.284-296
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• 2015

It has been thought that males tend to use their brain hemispheres more laterally than females. However, recent fMRI studies have shown that there may be no difference in brain lateralization between genders. Functional near-infrared spectroscopy (fNIRS) presents a unique opportunity to acquire real time measurements of blood oxygenation changes to observe neural activity specific to the brain's left and right hemispheres. Using an in-house built multichannel fNIRS system, brain lateralization was observed from seven males and four females according to specially designed tasks for left and right hemisphere activation. The Pearson correlation coefficient and a modified Lateralization Index metric for continuous wave fNIRS systems were calculated to quantify brain lateralization. The preliminary results point to no significant difference in lateral hemodynamic changes between the genders. However, the correlation of symmetrical channel pairs decreased as the experiments progressed. To further develop this study, the subject's performance and the removal of global interference must be implemented for an improved study of brain lateralization.

• BMB Reports
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• v.53 no.1
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• pp.20-27
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• 2020

Translocator protein (TSPO), also known as peripheral benzodiazepine receptor, is a transmembrane protein located on the outer mitochondria membrane (OMM) and mainly expressed in glial cells in the brain. Because of the close correlation of its expression level with neuropathology and therapeutic efficacies of several TSPO binding ligands under many neurological conditions, TSPO has been regarded as both biomarker and therapeutic target, and the biological functions of TSPO have been a major research focus. However, recent genetic studies with animal and cellular models revealed unexpected results contrary to the anticipated biological importance of TSPO and cast doubt on the action modes of the TSPO-binding drugs. In this review, we summarize recent controversial findings on the discrepancy between pharmacological and genetic studies of TSPO and suggest some future direction to understand this old and mysterious protein.

• BMB Reports
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• v.34 no.6
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• pp.559-565
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• 2001

Protein carboxyl O-methyltransferase (E.C.2.1.1.24) may play a role in the repair of aged protein that is spontaneously incorporated with isoaspartyl residues. The porcine brain carboxyl O-methyltransferase was cloned in the pET32 vector, and overexpressed in E.coh (BL21) that harbors pETPCMT, which encodes 227 amino acids, including tagging proteins at the N-terminus. The protein sequence of the cloned porcine brain PCMT (r-pbPCMT) shares a 98% identity with that of human erythrocyte PCMT and rat brain PCMT. It is 100% identical with that of bovine brain. The r-pbPCMT was purified using Ni-NTA affinity chromatography and digested by enterokinase in order to remove the protein tags. Then Superdex 75HR gel filtration chromatography was performed. The r-pbPCMT exhibited similar in vitro substrate specificities with the PCMT that was purified from porcine brain. The molecular weight of the enzyme was estimated to be 24.5 kDa on the SDS polyacrylamide gel electrophoresis. The $K_m$ value was $1.1{\times}10^{-7}\;M$ for S-adenosyl-L-methionine. S-adnosyl-L-homocysteine was a competitive type of inhibitor with the $K_i$ value of $1.38{\times}10^{-4}\;M$. The enzyme has optimal activity at pH 6.0 and $37^{\circ}C$. These results indicate that the expressed enzyme is functionally similar to the natural protein. It also suggests that it may be a suitable model to further understand the function of the mammalian enzyme.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.219-222
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• 2009

Rapid object recognition is one of the main stream research themes focusing to reveal how human recognizes object and interacts with environment in natural world. This field of study is of consequence in that it is highly important in evolutionary perspective to quickly see the external objects and judge their characteristics to plan future reactions. In this study, we investigated how human detect natural scene objects and categorize them in a limited time frame. We applied Magnetoencepahlogram (MEG) while participants were performing detection (e.g. object vs. texture) or basic-level categorization (e.g. cars vs. dogs) tasks to track the dynamic interaction in human brain for rapid object recognition process. The results revealed that detection and categorization involves different temporal and functional connections that correlated for the successful recognition process as a whole. These results imply that dynamics in the brain are important for our interaction with environment. The implication from this study can be further extended to investigate the effect of subconscious emotional factors on the dynamics of brain interactions during the rapid recognition process.