• Title/Summary/Keyword: Host reaction

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Optical properties of undoped and $Co^{2+}$-doped $Zn_4$$ GeSe_6$ single crystals ($Zn_4$$ GeSe_6$$Co^{2+}$를 첨가한 $Zn_4$$ GeSe_6$:$Co^{2+}$단결정의 광학적 특성)

  • 김덕태
    • Electrical & Electronic Materials
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    • v.10 no.2
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    • pp.105-112
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    • 1997
  • Undoped and Co$^{2+}$-doped Zn$_{4}$GeSe$_{6}$ single crystals were grown by the Chemical Transport Reaction method using iodine as a transporting agent. The crystal structure of these compounds determined by X-ray diffraction analysis was monoclinic structure. The direct energy gaps of these compounds were measured and the temperature dependence of the optical energy gap were closely investigated over the temperature range 10-290K. The temperature dependence of the optical energy gap is well presented by the Varshni equation. Also the optical absorption peaks of Zn$_{4}$GeSe$_{6}$ :Co$^{2+}$ single crystal observed, centered at 5437, 6079, 7142, 12950, 13462, 14786 and 15735 $cm^{-1}$ /, can be explained in terms of the electronic transitions of Co$^{2+}$ ions located at Td symmetry of the host materials. According to the crystal-field theory, the crystal-field, Racah and spin-orbit coupling parameters obtained from the absorption bands are given by Dq = 361$cm^{-1}$ /, B = 655$cm^{-1}$ / and .lambda. = 284$cm^{-1}$ / respectively.ively.

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Crystal Structure and Quantitative Phase Analysis of Multiphase Sample using RIETAN and MEED (RIETAN 및 MEED법에 의한 다상시료의 결정구조 및 정량상 분석)

  • 김광복;천희곤;조동율;신종근;구경완
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.303-307
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    • 2000
  • The crystal structure of ZnS fabricated by gas-liquid phase reaction was obtained by XRD and refined by RIETAN near R$_{wp}$ factor 10%. The increasement of HCP phase depended on extra H$_2$S gas and the lattice parameter and crystalline size changed by the relative ratio of multiphase. Using ZnS of the different multiphase ratio and crystalline size, sintered ZnS:Cu, Al green phosphor and the CL property resulted optimum luminescence in the range of 91~94% and 150~190$\AA$, respectably, FCC/HCP ratio and crystalline size. As changing of structure ratio, the reason of different luminescence property is now studying. As well as, after XRD pattern of TiO$_2$powder fitted by RIETAN and the structure factor using MEED method simulated about each atom of (002) plane. Additionally, we proposed RIETAN and MEED were the methods of the study of luminescence mechanism for many phosphor materials.s.

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Identification of Tomato Aspermy Virus (TAV) and Chrysanthemum Virus B (CVB) from Dendranthema indicum in Korea

  • Chung, Bong-Nam;Park, Gug-Seoun;Park, Yong-Moon
    • The Plant Pathology Journal
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    • v.15 no.2
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    • pp.119-123
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    • 1999
  • Chrysanthemums showing leaf mottling were collected from three southern locations in Korea in 1998. Two kinds of viruses were isolated from the leaves and were identified as tomato aspermy virus ch-TAV) and chrysanthemum virus B (ch-CVB), according to their host range, morphology, intracellular location, agar gel double diffusion test, and double-stranded RNA (dsRNA) analysis. The purified ch-TAV was spherical particles of approximately 29 nm in diameter and ch-CVB was filamentous particles of 685 nm long. Inclusion bodies were not observed in ch-TAV and/or ch-CVB infected chrysanthemum. ch-TAV showed positive serological reaction with TAV antiserum (ATCC-127) but not with CMV-pepper antiserum. In dsRNA analysis, four kinds of viral dsRNA were observed on ch-TAV and one viral dsRNA was shown on ch-CVB. Rate of co-infection with TAV and CVB in commercial chrysanthemums was 20.9%. On the other hand, infection with CVB alone was 97.2%. However, chrysanthemums naturally infected with TAV alone were not found.

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Allergina inhibits the progression of graft rejection, hypersensitivity, and collagen-induced autoimmune arthritis

  • Lee, C-W;Han, S-B;Yoon, P-S;Jeong, C-M;Lee, M-L;Kim, K-M;Yoon, Y-D;Kim, H-C;Park, S-K
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2002.11b
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    • pp.181-181
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    • 2002
  • The herbal combination allergina has been used for the treatment of inflammatory diseases in South Korea. In this study, we investigated the immunosuppressive activities of allergina in more detail. Acute graft-versus-host disease (GVHD) is a major cause of morbidity and mortality in patients undergoing allogeneic bone marrow transplantation.(omitted)

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Differential expression of the 27 kDa cathepsin L-like cysteine protease in developmental stages of Spirometra erinacei

  • Kong, Yoon;Yun, Doo-Hee;Cho, Seung-Yull;Sohn, Woon-Mok;Chung, Young-Bae;Kang, Shin-Yong
    • Parasites, Hosts and Diseases
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    • v.38 no.3
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    • pp.195-199
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    • 2000
  • The 27 kDa cathepsin L-like cysteine protease of Spirometra erinocei plerocercoid is known to play an important function in tissue penetration, nutrient uptake and immune modulation in human sparganosis. In the present study, the expression of this enzyme was examined at different developmental stages of S. erinacei including immature egg, coracidium, plerocercoid in tadpole and rat, and adult Proteolytic activity against carboxybenzoyl-phenylalanyl-arginyl-7-amino-4-rnethylcournarin was do tooted in the extracts of coracidia and plerocercoid while no activity was observed in those of immature egg and adult. The specific activity in coraridial extracts was lower than that in the plerocercoid. Reverse transcription-polymerase chain reaction and Northern biol analysis demonstrated that the gene was expressed in the coracidium and plerocercoid but not in immature egg and adult. These results suggest that the 27 kDa cysteine protease is only expressed in the stages involving active migration of the parasite in the host tissue.

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Skin Test for Paragonimiasis among Schoolchildren and Villagers in Namback District, Luangprabang Province, Lao PDR

  • Song, Hyun-Ouk;Min, Duk-Young;Rim, Han-Jong;Youthanavanh, Vonghachack;Daluny, Bouakhasith;Sengdara, Vongsouvan;Virasack, Banouvong;Bounlay, Phommasak
    • Parasites, Hosts and Diseases
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    • v.46 no.3
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    • pp.179-182
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    • 2008
  • As a part of a broader effort to determine the status of Paragonimus species infection in Lao PDR, an epidemiological survey was conducted on villagers and schoolchildren in Namback District between 2003 and 2005. Among 308 villagers and 633 primary and secondary schoolchildren, 156 villagers and 92 children evidenced a positive reaction on a Paragonimus skin test. Only 4 schoolchildren out of 128 skin test-positive cases had Paragonimus sp. eggs in their sputum, all of which was collected on 1 day. Several types of crabs, which were identified as the second intermediate host of the Paragonimus species, were collected from markets and streams in a paragonimiasis endemic area for the inspection of metacercariae. Among the examined crabs, only "rock crabs" (Indochinamon au) harbored Paragonimus sp. metacercariae, and it is speculated that the life cycle of Paragonimus sp. was maintained via rock crabs in Namback District, Lao PDR.

Susceptibility of Koi, Koi×Red Common Carp, and Red Common Carp×Koi to Koi Herpesvirus (KHV)

  • Hwang, Ju-Ae;Kim, Jung Eun;Kim, Hyeong Su;Park, Junseong;Lee, Jeong-Ho
    • Development and Reproduction
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    • v.24 no.4
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    • pp.277-285
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    • 2020
  • The disease-causing koi herpes virus (KHV), also known as cyprinid herpesvirus-3 (CyHV3), causes mass mortality of koi and carp. Koi (Cyprinus carpio) is a host for KHV, one of 12 virus species in the Alloherpesviridae family. We examined the effects of KHV disease koi (KK), and on koi×red common carp (KR) and red common carp×koi (RK) cross, using a virus challenge test. The infected fish had clinical signs that included gill necrosis and skin lesions. The RK and KR were highly more resistant (cumulative mortality: RK; 6% and KR; 8%) to KHV infection than KK fish (cumulative mortality: 28%). KHV DNA was confirmed in the tissues of all dead fish in groups by use of polymerase chain reaction (PCR), and the presence of the KHV protein in kidney was confirmed by immunohistochemistry. Histological analysis showed severe gill lesions and fusion of the lamellae in KK fish, but less severe damage in RK fish. In immunohistochemistry analysis, the KHV protein localized in the cytoplasm of infected kidney cells of KK, but the cross groups had lower levels of KHV antigen. Our data indicate that the cross groups had increased resistance to KHV disease.

Ce $L_Ⅲ$-edge X-ray Absorption Spectroscopic Studies on the Tetrameric Ce-polyoxyhydroxy Cation Intercalated Aluminosilicate

  • Yun, Ju Byeong;Hwang, Seong Ho;Kim, Dong Guk;Gang, Seong Gu;Choe, Jin Ho
    • Bulletin of the Korean Chemical Society
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    • v.21 no.3
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    • pp.305-309
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    • 2000
  • The cerium ion intercalated aluminosilicate was prepared by ion exchange reaction between $Na^+$ in montmorillonite and $Ce^{+4}$ in aqueous solution. The X-ray absorption near edge structrure(XANES) analyses indicate that the $Ce^{+4}$ ions are partially reduced to the $Ce^{+3}$ ones during the intercalation into layered aluminosilicate due to a charge transfer between host and intercalant. From the EXAFS analysis, two different (Ce-O) bonding pairs could be characterized with the distances and coordination numbers of 2.31 $({\pm}0.02){\AA}$ ${\times}$ 8.2 $({\pm}1.5)$ and 2.66 $({\pm}0.02){\AA}$ ${\times}$ 2.7 $({\pm}1.0)$, respectively, with the oxygen atoms as the first nearest neighbor, and two (Ce-Ce) pairs at 3.78 ${\AA}$ as the second neighbor. It is therefore concluded that the most probable Ce-species stabilized in the interlayer space of aluminosilicate after the intercalation is the tetrameric Ce-polyoxy/hydorxy cations with the mixed valent state of 0.75 $Ce^{+4}$.0.25 $Ce^{+3}$.

Pathogenicity of infectious in vitro transcripts and comparison of RNA3 of Alfalfa mosaic virus Korean isolates

  • J.H. Ha;Park, J.K.;K.H. Ryu
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.146.2-147
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    • 2003
  • Two Korean isolates of Alfalfa mosaic virus (AHV-AZ, AMV-KR) were isolated from azuki bean and potato plants, respectively, and their pathologies were confirmed on some susceptible host plants including pepper, tobacco and red bean plants. Full length cDNAs to RNA1, RNA2 and RNA3 of the two Korean strains were amplified using the long-template reverse transcription (RT)-polymerase chain reaction (PCR) method. RT-PCR products covering entire regions for the three AMV genome RNAs were cloned. RNA transcripts were synthesized in vitro from each clones using T7 RNA polymerase and infectivity test was peformed in 9 reassortment sets of transcripts. All the combinations of reassorted transcripts were found to be infectious when inoculated onto Nicotiana benthamiana plants, and were not distinguishable to those of wild types. The full-length cDNA clones that were confirmed infectious were sequenced their nucleotide sequences. We will discuss sequence analysis of the two Korean isolates of AMV genomic RNA3 and compare reported foreign isolates of AMV.

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Bidirectional Interactions between Green Tea (GT) Polyphenols and Human Gut Bacteria

  • Se Rin Choi;Hyunji Lee;Digar Singh;Donghyun Cho;Jin-Oh Chung;Jong-Hwa Roh;Wan-Gi Kim;Choong Hwan Lee
    • Journal of Microbiology and Biotechnology
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    • v.33 no.10
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    • pp.1317-1328
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    • 2023
  • Green tea (GT) polyphenols undergo extensive metabolism within gastrointestinal tract (GIT), where their derivatives compounds potentially modulate the gut microbiome. This biotransformation process involves a cascade of exclusive gut microbial enzymes which chemically modify the GT polyphenols influencing both their bioactivity and bioavailability in host. Herein, we examined the in vitro interactions between 37 different human gut microbiota and the GT polyphenols. UHPLC-LTQ-Orbitrap-MS/MS analysis of the culture broth extracts unravel that genera Adlercreutzia, Eggerthella and Lactiplantibacillus plantarum KACC11451 promoted C-ring opening reaction in GT catechins. In addition, L. plantarum also hydrolyzed catechin galloyl esters to produce gallic acid and pyrogallol, and also converted flavonoid glycosides to their aglycone derivatives. Biotransformation of GT polyphenols into derivative compounds enhanced their antioxidant bioactivities in culture broth extracts. Considering the effects of GT polyphenols on specific growth rates of gut bacteria, we noted that GT polyphenols and their derivate compounds inhibited most species in phylum Actinobacteria, Bacteroides, and Firmicutes except genus Lactobacillus. The present study delineates the likely mechanisms involved in the metabolism and bioavailability of GT polyphenols upon exposure to gut microbiota. Further, widening this workflow to understand the metabolism of various other dietary polyphenols can unravel their biotransformation mechanisms and associated functions in human GIT.