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Search Results: 1 - 10 of 45 matches for " Seonghee Paek "
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The Actinobacillus pleuropneumoniae HMW1C-Like Glycosyltransferase Mediates N-Linked Glycosylation of the Haemophilus influenzae HMW1 Adhesin
Kyoung-Jae Choi,Susan Grass,Seonghee Paek,Joseph W. St. Geme III,Hye-Jeong Yeo
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015888
Abstract: The Haemophilus influenzae HMW1 adhesin is an important virulence exoprotein that is secreted via the two-partner secretion pathway and is glycosylated at multiple asparagine residues in consensus N-linked sequons. Unlike the heavily branched glycans found in eukaryotic N-linked glycoproteins, the modifying glycan structures in HMW1 are mono-hexoses or di-hexoses. Recent work demonstrated that the H. influenzae HMW1C protein is the glycosyltransferase responsible for transferring glucose and galactose to the acceptor sites of HMW1. An Actinobacillus pleuropneumoniae protein designated ApHMW1C shares high-level homology with HMW1C and has been assigned to the GT41 family, which otherwise contains only O-glycosyltransferases. In this study, we demonstrated that ApHMW1C has N-glycosyltransferase activity and is able to transfer glucose and galactose to known asparagine sites in HMW1. In addition, we found that ApHMW1C is able to complement a deficiency of HMW1C and mediate HMW1 glycosylation and adhesive activity in whole bacteria. Initial structure-function studies suggested that ApHMW1C consists of two domains, including a 15-kDa N-terminal domain and a 55-kDa C-terminal domain harboring glycosyltransferase activity. These findings suggest a new subfamily of HMW1C-like glycosyltransferases distinct from other GT41 family O-glycosyltransferases.
Synthesis of Tetrasubstituted Alkenes via Metathesis
Seung-Mann Paek
Molecules , 2012, DOI: 10.3390/molecules17033348
Abstract: Fully substituted olefin generation via metathesis is presented. Catalyst development, optimization of reaction conditions and substrate screening are included. In addition, asymmetric alkene metathesis, the cross metathesis reaction for this transformation and its application in natural products will be discussed.
Conversation as Action Under Uncertainty
Tim Paek,Eric J. Horvitz
Computer Science , 2013,
Abstract: Conversations abound with uncetainties of various kinds. Treating conversation as inference and decision making under uncertainty, we propose a task independent, multimodal architecture for supporting robust continuous spoken dialog called Quartet. We introduce four interdependent levels of analysis, and describe representations, inference procedures, and decision strategies for managing uncertainties within and between the levels. We highlight the approach by reviewing interactions between a user and two spoken dialog systems developed using the Quartet architecture: Prsenter, a prototype system for navigating Microsoft PowerPoint presentations, and the Bayesian Receptionist, a prototype system for dealing with tasks typically handled by front desk receptionists at the Microsoft corporate campus.
Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens
Seonghee Lee,Yasuhiro Ishiga,Kristen Clermont,Kirankumar?S. Mysore
PeerJ , 2013, DOI: 10.7717/peerj.34
Abstract: Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR), which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS)-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.
Interventionelle Pr nataltherapie - der Fetus als Patient
Strauss A,Hepp H,Paek B
Speculum - Zeitschrift für Gyn?kologie und Geburtshilfe , 2001,
Abstract: Mit dem rasanten Fortschritt pr nataler Diagnostik wurden auch Hoffnungen auf therapeutische Optionen geweckt. Eine Vielzahl, aber bei weitem nicht alle Probleme und technischen Schwierigkeiten konnten in den letzten Jahren gel st werden. Die Indikation zur invasiven Pr nataltherapie ist der Gruppe fetaler Erkrankungen bzw. Anomalien vorbehalten, welche mit einer progressiven Sch digung der Organentwicklung einhergehen. Die transabdominelle Punktion, fetoskopische "minimal invasive" und offene Pr natalchirurgie stellen die 3 Kategorien pr nataler Interventionsm glichkeiten dar. Amnioninfusion, Amniondrainage, Erythrozyten-/ Thrombozytentransfusion, Drainage intrakavit rer Flüssigkeit, dauerhafte intraamniale Shuntanlage und direkte, intravaskul re medikament se Therapie bezeichnen das Anwendungsgebiet der transabdominellen Nadelprozeduren. Endoskopische Eingriffe stehen bei Zwillingsschwangerschaften, kompliziert durch ein fetofetales Transfusionssyndrom oder eine TRAP-Sequenz zur Disposition. Ebenso kommen diese Eingriffe bei der Zwerchfellhernie, bei der Chylothoraxdrainage, bei obstruktiven Uropathien und bei intrauterinen Tumoren zur Anwendung. Offene fetale Operationen mit mütterlicher Hysterotomie stellen h ufig den Ausgangspunkt neuer Behandlungsoptionen dar. In der Folge werden sie jedoch zunehmend durch endoskopische Techniken mit geringerem Eingriffsrisiko abgel st. Im Zuge der Entwicklung expandierender Therapieindikationen gewinnen kindliche Analgesie und der sorgf ltige Umgang mit klinisch-ethischen Belangen bei Beratung und Eingriff zus tzliches Gewicht. Die differenzierte Entwicklung invasiver Pr nataltherapie widerlegt nachdrücklich das nach wie vor g ngige Vorurteil: Pr natale Therapie = Abruptio. Diese Zusammenfassung soll ein aktuelles Abbild etablierter wie experimenteller intrauteriner Therapiem glichkeiten geben.
Ring Expansion of Vinylaziridines through the Strain-Release Pericyclic Reaction: Recent Developments and Applications
Yu Mi Heo,Seung-Mann Paek
Molecules , 2013, DOI: 10.3390/molecules18089650
Abstract: Recent syntheses of azetidines, pyrrolidines, piperidines and azepines through cycloaddition or sigmatropic rearrangements of vinylaziridines are described. Applications to natural product synthesis and mechanistic investigations are also summarized.
Plant RNA binding proteins for control of RNA virus infection
Sung Un Huh,Kyung-Hee Paek
Frontiers in Physiology , 2013, DOI: 10.3389/fphys.2013.00397
Abstract: Plant RNA viruses have effective strategies to infect host plants through either direct or indirect interactions with various host proteins, thus suppressing the host immune system. When plant RNA viruses enter host cells exposed RNAs of viruses are recognized by the host immune system through processes such as siRNA-dependent silencing. Interestingly, some host RNA binding proteins have been involved in the inhibition of RNA virus replication, movement, and translation through RNA-specific binding. Host plants intensively use RNA binding proteins for defense against viral infections in nature. In this mini review, we will summarize the function of some host RNA binding proteins which act in a sequence-specific binding manner to the infecting virus RNA. It is important to understand how plants effectively suppress RNA virus infections via RNA binding proteins, and this defense system can be potentially developed as a synthetic virus defense strategy for use in crop engineering.
Association between FGFR1OP2/wit3.0 Polymorphisms and Residual Ridge Resorption of Mandible in Korean Population
Jee Hwan Kim, Min Young Oh, Janghyun Paek, Jaehoon Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042734
Abstract: Background A previous study on the genetic association between single nucleotide polymorphisms in FGFR1OP2/wit3.0 and the long term atrophy of edentulous mandible hypothesized that the excessive jawbone atrophy after dental extraction may be associated with abnormal oral mucosa contraction induced by the FGFR1OP2/wit 3.0 gene. It was reported that the minor allele of rs840869 or rs859024 in FGFR1OP2/wit3.0 was associated with the excessive atrophy of edentulous mandible. The present study represents an attempt to replicate the results of this previous study and to examine the genetic association between polymorphisms in FGFR1OP2 and residual ridge resorption of mandible in a Korean population. Methodology/Principal Findings 134 subjects (70.46±9.02 years) with partially or completely edentulous mandible were recruited. The mandibular bone height was measured following the protocol of the American College of Prosthodontists (ACP). From 24 subjects, seven variants in FGFR1OP2 were discovered and four of them were novel. Selected SNPs that are not in high LD at r2 threshold of 0.8 were genotyped for the remaining population. There was no frequency of the minor allele of SNP rs859024 in Korean population. SNP rs840869 was not associated with residual ridge resorption (p = 0.479). The bone height of the subject with the ss518063493 minor allele (8.52 mm) was shorter than that of those subjects with major alleles (18.96±5.33 mm, p = 0.053). Conclusions/Significance The patient with minor allele of ss518063493 may be associated with excessive atrophy of edentulous mandible whereas the patients with that of rs840869 are not associated in Korean population. The result from this study may assist in developing a novel genetic diagnostic test and be useful in identifying Koreans susceptible to developing excessive jawbone atrophy after dental extraction.
Synthetic Studies on Bioactive Natural Polyketides: Intramolecular Nitrile Oxide-Olefin Cycloaddition Approach for Construction of a Macrolactone Skeleton of Macrosphelide B
Seung-Mann Paek,Young-Ger Suh
Molecules , 2011, DOI: 10.3390/molecules16064850
Abstract: Studies on the synthesis of macrosphelide B via an intramolecular nitrile oxide-olefin cycloaddition (INOC) is described. In particular, an asymmetric INOC approach using phase transfer catalysts seems to be a potentially efficient and versatile procedure for the construction of the macrolactone skeleton of macrosphelide B in terms of facial selectivity. Our preliminary and unprecedented stereoselective procedure is anticipated to be usefully applied through further studies for the synthesis of the macrosphelide family.
Adventitious Roots and Secondary Metabolism

Hosakatte Niranjana Murthy,Eun Joo Hahn,Kee Yoeup Paek,

微生物学报 , 2008,
Abstract: Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high- value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.
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