• Applied Microscopy
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• 제17권1호
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• pp.161-168
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• 1987

The elongated filamentous haustorial cells, hyphae, of Cuscuta australis R. Brown penetrated into the vascular tissues of the host plant Trifolium repens L. were studied by the light and electron microscopes. The hyphae reached the host xylem were invaded into the host vessels and then they grew within the host vessels. Finally these hyphae were differentiated into the water conducting elements, xylary hyphae, by thickening of the secondary walls. The hyphae reached the host phloem were branched at the apical regions. These hyphae possessed thin-layered cytoplasm involving the typical features of sieve elements such as the parallel arrays of smooth endoplasmic reticulum, plastids with the clusters of fine starch granules, and mitochondria with the dilated cristae. It was indicated that these hyphae were differentiated into the nutrients conducting elements, phloic hyphae. The structures described were compared with those of other parasitic plants and were discussed in view of the translocation of materials from host to parasite.

• 천문학회보
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• 제42권1호
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• pp.53.2-53.2
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• 2017

The origin of the well-known correlation between Hubble residual of Type Ia Supernova (SN Ia) and mass of their host galaxies is yet to be fully understood. In our first paper of our YOnsei Evolutionary Supernovae Evolutionary Investigation (YONSEI) project, we found a significant (${\sim}3.9{\sigma}$) correlation between host galaxy mass (velocity dispersion) and population age from high S/N host spectra observed using LCO 2.5 m telescope. Since there is no correlation with metallicity, our result suggests that stellar population age is mainly responsible for the relation between host mass and HR. In order to explore this more directly, we have subsequently observed more sample of nearby early-type host galaxies using MMT 6.5 m telescope. In this poster presentation, we will report our progress in this project and show the preliminary results from our MMT observations.

• ALGAE
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• 제20권3호
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• pp.225-232
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• 2005

Optical microscopy of recently living and cleared material of the fucoid, Ascophyllum nodosum (L.) Le Jolis, revealed novel aspects of its interaction with the ascomycete Mycophycias ascophylli (Cotton) Kohlmeyer and Kohlmeyer (previously Mycosphaerella ascophylli Cotton). Most host cells are associated with hyphae by lateral attachment of cell walls. Hyphae form extensive networks throughout the host thallus and show considerable differentiation in the various host tissues. In the base of epidermal cells, hyphae form multicellular rings around each host cell to produce a continuous network. In medullary regions, long, relatively unbranched and longitudinally aligned hyphae occur, with radial branches extending into cortical regions. Scattered in the inner cortex of host tissue are numerous multicellular nodes of smaller, polygonal to irregular shaped cells with five or more radiating arms of hyphae. Individual hyphal cells show a variety of specializations including swellings and appressoria-like attachments to some host cells. These observations provide the morphological basis for the mutualistic symbiosis supported by recent experimental work. We conclude that this association is best described by the term “symbiotum.”

• 한국환경과학회지
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• 제17권12호
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• pp.1373-1380
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• 2008

Anthracene appended new host compounds have been synthesized by imine reaction. Fluorescent open chain host compounds Trisanthryl-tris(2-aminoethyl)imine 1 was synthesized from the reaction of tris(2-aminoethyl)amine and anthracene-9-carboxaldehyde in EtOH. Tris-10-chloroanthryl-tris(2-aminoethyl)imine 2 was synthesized from tris(2-aminoethyl)amine and 10-chloro-9-anthraldehyde in EtOH. The structures of all reaction product were identified by $^1H$ NMR, $^{13}C$ NMR, GC/MS, FAB Mass, IR spectrum and DSC. Cation complexation behavior was investigated by fluorescence spectroscopy measurements. The capability of transition metals cation recognition between fluorescent open chain host compound 1, 2 were investigated with $Co^{2+},\;Ni^{2+}\;and\;Cu^{2+}$. The fluorescence intensity was increased by host compounds corresponding guest cations. The relative order of fluorescence intensity changes were $Co^{2+}>Cu^{2+}>Ni^{2+}$. Compound 2 is very sensitive fluorescent sensor of $Co^{2+}$ ion.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1549-1558
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• 2017

Despite significant efforts to improve the treatment of tuberculosis (TB), it remains a prevalent infectious disease worldwide owing to the limitations of current TB therapeutic regimens. Recent work on novel TB treatment strategies has suggested that directly targeting host factors may be beneficial for TB treatment. Such strategies, termed host-directed therapeutics (HDTs), focus on host-pathogen interactions. HDTs may be more effective than the currently approved TB drugs, which are limited by the long durations of treatment needed and the emergence of drug-resistant strains. Targets of HDTs include host factors such as cytokines, immune checkpoints, immune cell functions, and essential enzyme activities. This review article discusses examples of potentially promising HDTs and introduces novel approaches for their development.

• Bulletin of the Korean Chemical Society
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• 제22권11호
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• pp.1248-1254
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• 2001

The conformations and energies of p-tert-butylcalix[4]crown-6-ether (1) and its alkyl ammonium complexes have been calculated by ab initio HF/6-31G quantum mechanics method. The cone conformation was found to be most stable for free host 1. We hav e determined the binding site of these host-guest complexes focusing on the crown-6-ether or p-tert-butylcalix[4]arene pocket of the cone conformation of host molecule 1. The primary binding site of host 1 for the recognition of alkyl ammonium guests was confirmed to be the central part of the crown moiety of cone conformation. The complexation energy calculations revealed that the ammonium cation without alkyl group showed the highest complexation efficiency when combined with host 1, that is in satisfactory agreement with the experimental results.

• BMB Reports
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• 제56권3호
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• pp.133-139
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• 2023

The human intestine is home to a dense community of microbiota that plays a key role in human health and disease. Nutrients are essential regulators of both host and microbial physiology and function as key coordinators of host-microbe interactions. Therefore, understanding the specific roles and underlying mechanisms of each nutrient in regulating the host-microbe interactions will be essential in developing new strategies for improving human health through microbiota and nutrient intervention. This review will give a basic overview of the role of vitamin A, an essential micronutrient, on human health, and highlight recent findings on the mechanisms by which it regulates the host-microbe interactions.

• 무역상무연구
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• 제71권
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• pp.195-216
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• 2016

In determining the content of the FET standard, the tribunals stated protection of investor's legitimate expectations, due process and denial of justice, transparency, discrimination and arbitrariness, good faith, etc. The most major elements of the FET standard is the protection of the investor's legitimate and reasonable expectations. It is necessary to consider whether it is possible to what the expectations of investors are protected as legitimate and it is formed under any circumstances. If host state frustrate investor's legitimate expectations, it found a breach of the FET. The host state's specific assurance may reinforce investor's expectations, but such explicit statement is not always necessary. The host state must preserve a stable environment for investments. However, It must not be understood as the inalterability of the host state's legal framework. It implies that the host state's subsequent changes should be made consistently and predictably. The host state is entitled to exercise a reasonable regulatory authority to respond to changing circumstances in the public purpose. Therefore, whether the violation FET shall be determined through a balanced against the investor's legitimate expectations and the host state's reasonable regulatory exercise in the public interest. And investor should keep in mind that the principle of proportionality is applied unless host state provides stabilization clause or similar commitments to investor. Also host state should establish the basis of an argument about reasonable regulatory authority for public interest.

• 한국발생생물학회지:발생과생식
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• 제2권1호
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• pp.81-87
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• 1998

한국산 작은대칭이 (Anodonta arcaeformis flavotincta)의 유생발생 중 유생(glochidium)을 숙주어류인 붕어(carassius auratus)에 감염시켜 유생의 피낭형성과정(부착부위, 부착후 탈락가지의 시기)을 알아보기 위해, 주사전자현미경을 이용하여 관찰한 결과 다음과 같은 결론을 얻었다. 유생들은 30분내에 숙주어류의 니트러미, 구강 그리고 아가미에 부착되었다. 이 연구에서 유생이 부착된 숙주어류의 지느러미를 시간별로 관찰하였다. 유생의 부착률은 숙주어류의 가슴지느러미,꼬리지느러미, 배지느러미에 각각 30%, 22%, 17%였다. 피낭형성과정은 천천히 진행되었다. 1차 피낭형성은 24시간에서 27시간째에 이루어졌고, 그리고 5일 내지 6일째 유생은 숙주조직의 상피세포로 완전히 덮였다. 유패의 탈락과정은 숙주에 감염시킨후 8일째에 관찰되었다. 유생의 대부분은 15일 이내에 숙주어류의 피낭으로부터 탈락되었다. 유생이 숙주에 부착되기 전과 숙주어류의 피낭으로부터 탈락된 유패의 크기는 변화가 없었다.

• The Plant Pathology Journal
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• 제24권3호
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• pp.337-351
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• 2008

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes(G) accounted for largest(78.4%) proportion of the total sum of squares(SS), followed by 16.5% due to the pathogen isolates(I) and 5.1% due to the $I{\times}G$ interactions. Application of the Additive Main effects and Multiplicative Interaction(AMMI) model revealed that the first two interaction principal component axes(IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index '$D_i$' values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA-2 scores, low $D_i$ values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.