• Title/Summary/Keyword: SAM protein

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Sensitivity Alterable Biosensor Based on Gated Lateral BJT for CRP Detection

  • Yuan, Heng;Kang, Byoung-Ho;Lee, Jae-Sung;Jeong, Hyun-Min;Yeom, Se-Hyuk;Kim, Kyu-Jin;Kwon, Dae-Hyuk;Kang, Shin-Won
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.13 no.1
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    • pp.1-7
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    • 2013
  • In this paper, a biosensor based on a gated lateral bipolar junction transistor (BJT) is proposed. The gated lateral BJT can function as both a metal-oxide-semiconductor field-effect transistor (MOSFET) and a BJT. By using the self-assembled monolayer (SAM) method, the C-reactive protein antibodies were immobilized on the floating gate of the device as the sensing membrane. Through the experiments, the characteristics of the biosensor were analyzed in this study. According to the results, it is indicated that the gated lateral BJT device can be successfully applied as a biosensor. Additionally, we found that the sensitivity of the gated lateral BJT can be varied by adjusting the emitter (source) bias.

Fabrication and Characteristics of MOSFET Protein Sensor Using Nano SAMs (자기조립 단분자막을 이용한 MOSFET형 단백질 센서의 제작 및 특성)

  • Han, Seung-Woo;Park, Keun-Yong;Kim, Min-Suk;Kim, Hong-Seok;Bae, Young-Seuk;Choi, Sie-Young
    • Journal of Sensor Science and Technology
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    • v.13 no.2
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    • pp.90-95
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    • 2004
  • Protein and gene detection have been growing importance in medical diagnostics. Field effect transistor (FET) - type biosensors have many advantages such as miniaturization, standardization, and mass-production. In this work, we have fabricated metal-oxide-semiconductor (MOS) FET that operates as molecular recognitions based electronic sensor. Measurements were taken with the devices under phosphate buffered saline solution. The drain current ($I_{D}$) was decreased after forming self-assembled mono-layers (SAMs) used to capture the protein, which resulted from the negative charges of SAMs, and increased after forming protein by 11.5% at $V_{G}$ = 0 V due to the positive charges of protein.

Correlation between Protein Methylation and Hepatotoxicity (단백질메칠화 반응과 간독성간의 상관관계)

  • 김재현;박창원;이주한;백윤기;문화회;홍성렬;이향우
    • Biomolecules & Therapeutics
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    • v.2 no.1
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    • pp.47-53
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    • 1994
  • The methylation response as well as the level of methyl donor substance, 5-adenosyl-L-methionine (SAM) has been suggested to be related to hepatotoxicity including hepatocarcinogenesis. But direct correlation between protein methylation and hepatotoxicity has not been established to the present. To observe relationship between protein methylation and short-term hepatotoxicity induced by chemical substances, the activities of protein methylase I and II (PM I, PM II) were examined in cytosolic fraction of SD rat treated orally with acetaminophen(AA), $\alpha$-naphtyl-isothiocyanate (ANIT) and tetracycline (TC) that was known to produce necrosis, cholestasis and steatosis respectively. To evaluate the degree of hepatotoxicity induced by each chemicals, we observed the serum levels of indicative parameters and histopathological alteration. In AA treated group, the activities of PM I were increased at 6, 12 hours after administration, prior to the appearance of the hepatotoxicity by clinical parameters. It was suggested that the levels of PM I were related with the initial stage of hepatotoxic mechanism induced by AA. In ANIT treated group, though most of clinical parameters were significantly increased at 24, 48 hours after administration, the activity of PM I was not changed, indicating that ANIT induced hepatotoxicity was not coupled to protein methylation.

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Investigation of post-translational modification of the secreted protein expressed in insect cell lines using baculovirus expression vector system(BEVS)

  • Yun, Eun-Young;Goo, Tae-Won;Kim, Sung-Wan;Park, Kwang-Ho;Hwang, Jae-Sam;Kang, Seok-Woo;Kwon, O-Yu
    • Proceedings of the Korean Society of Sericultural Science Conference
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    • 2003.04a
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    • pp.82-83
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    • 2003
  • In previous experiment, we reported when the heterologous protein is expressed by using baculovirus expression vector system (BEVS), although the amount of intracellular protein is abundant, the amount of extracellular Protein is poor. As the link in the chain of the research, we investigated the secretory pathway, important in case of the secretory protein, of the protein expressed in insect cells using BEVS. (omitted)

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Microcantilever biosensor: sensing platform, surface characterization and multiscale modeling

  • Chen, Chuin-Shan;Kuan, Shu;Chang, Tzu-Hsuan;Chou, Chia-Ching;Chang, Shu-Wei;Huang, Long-Sun
    • Smart Structures and Systems
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    • v.8 no.1
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    • pp.17-37
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    • 2011
  • The microcantilever (MCL) sensor is one of the most promising platforms for next-generation label-free biosensing applications. It outperforms conventional label-free detection methods in terms of portability and parallelization. In this paper, an overview of recent advances in our understanding of the coupling between biomolecular interactions and MCL responses is given. A dual compact optical MCL sensing platform was built to enable biosensing experiments both in gas-phase environments and in solutions. The thermal bimorph effect was found to be an effective nanomanipulator for the MCL platform calibration. The study of the alkanethiol self-assembly monolayer (SAM) chain length effect revealed that 1-octanethiol ($C_8H_{17}SH$) induced a larger deflection than that from 1-dodecanethiol ($C_{12}H_{25}SH$) in solutions. Using the clinically relevant biomarker C-reactive protein (CRP), we revealed that the analytical sensitivity of the MCL reached a diagnostic level of $1{\sim}500{\mu}g/ml$ within a 7% coefficient of variation. Using grazing incident x-ray diffractometer (GIXRD) analysis, we found that the gold surface was dominated by the (111) crystalline plane. Moreover, using X-ray photoelectron spectroscopy (XPS) analysis, we confirmed that the Au-S covalent bonds occurred in SAM adsorption whereas CRP molecular bindings occurred in protein analysis. First principles density functional theory (DFT) simulations were also used to examine biomolecular adsorption mechanisms. Multiscale modeling was then developed to connect the interactions at the molecular level with the MCL mechanical response. The alkanethiol SAM chain length effect in air was successfully predicted using the multiscale scheme.

Cytotoxicity of T-2 Toxin on Primary Cultures of Rat Hepatocytes

  • Kim, Hwan-Mook;Kim, Byung-Sam;Choe, Suck-Young;Yang, Kyu-Hwan
    • Toxicological Research
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    • v.4 no.1
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    • pp.37-45
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    • 1988
  • Primary cultures of adult rat hepatocytes were used to study in vitro cytotoxic effects of T-2 toxin on liver cells. When T-2 toxin was added to the culture, a significant depression of the hormonal induction of ${\alpha}$-aminoisobutyric acid (AIB) uptake and tyrosine aminotransferase (TAT) activity was observed. However, T-2 toxin did not affect the uptake of ouabain into hepatocytes. Protein synthesis was inhibited by T-2 toxin, but RNA synthesis was not severely affected. The inhibitory effects of T-2 toxin on protein synthesis was diminished rapidly with culture time and the hepatocytes culture maintained control level of protein synthesis within 24 hrs.

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Identification of Dopa decarboxylase associated protein from Bombyx mori

  • Hwang, Jae-Sam;Kim, Sung-Kuk;Kang, Seok-Woo;Goo, Tae-Won;Yun, Eun-Young;Park, Kwang-Ho;Chang, Jong-Soo
    • Proceedings of the Korean Society of Sericultural Science Conference
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    • 2003.10a
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    • pp.97-98
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    • 2003
  • Current study was aimed to understand an interaction between Dopa decarboxylase (DDC) and proteins that specifically binds to DDC in the silkworm, Bombyx mori. Materials and Methods: Materials-Animal: Bombyx mori Construction of GST fusion protein Preparation of lysates: Protein extracted from whole body of Bombyx mori Methods-In vitro binding assay with lysates, Peptide sequence and RACE-PCR (omitted)

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Identification and Characterization of Protein Arginine Methyltransferase 1 in Acanthamoeba castellanii

  • Moon, Eun-Kyung;Kong, Hyun-Hee;Hong, Yeonchul;Lee, Hae-Ahm;Quan, Fu-Shi
    • Parasites, Hosts and Diseases
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    • v.55 no.2
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    • pp.109-114
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    • 2017
  • Protein arginine methyltransferase (PRMT) is an important epigenetic regulator in eukaryotic cells. During encystation, an essential process for Acanthamoeba survival, the expression of a lot of genes involved in the encystation process has to be regulated in order to be induced or inhibited. However, the regulation mechanism of these genes is yet unknown. In this study, the full-length 1,059 bp cDNA sequence of Acanthamoeba castellanii PRMT1 (AcPRMT1) was cloned for the first time. The AcPRMT1 protein comprised of 352 amino acids with a SAM-dependent methyltransferase PRMT-type domain. The expression level of AcPRMT1 was highly increased during encystation of A. castellanii. The EGFP-AcPRMT1 fusion protein was distributed over the cytoplasm, but it was mainly localized in the nucleus of Acanthamoeba. Knock down of AcPRMT1 by synthetic siRNA with a complementary sequence failed to form mature cysts. These findings suggested that AcPRMT1 plays a critical role in the regulation of encystation of A. castellanii. The target gene of AcPRMT1 regulation and the detailed mechanisms need to be investigated by further studies.