• Title/Summary/Keyword: helix

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Site-directed Mutagenesis of Five Conserved Residues of Subunit I of the Cytochrome cbb3 Oxidase in Rhodobacter capsulatus

  • Ozturk, Mehmet;Gurel, Ekrem;Watmough, Nicholas J.;Mandaci, Sevnur
    • BMB Reports
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    • v.40 no.5
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    • pp.697-707
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    • 2007
  • Cytochrome $cbb_3$ oxidase is a member of the heme-copper oxidase superfamily that catalyses the reduction of molecular oxygen to the water and conserves the liberated energy in the form of a proton gradient. Comparison of the amino acid sequences of subunit I from different classes of heme-copper oxidases showed that transmembrane helix VIII and the loop between transmembrane helices IX and X contain five highly conserved polar residues; Ser333, Ser340, Thr350, Asn390 and Thr394. To determine the relationship between these conserved amino acids and the activity and assembly of the $cbb_3$ oxidase in Rhodobacter capsulatus, each of these five conserved amino acids was substituted for alanine by site-directed mutagenesis. The effects of these mutations on catalytic activity were determined using a NADI plate assay and by measurements of the rate of oxygen consumption. The consequence of these mutations for the structural integrity of the $cbb_3$ oxidase was determined by SDS-PAGE analysis of chromatophore membranes followed by TMBZ staining. The results indicate that the Asn390Ala mutation led to a complete loss of enzyme activity and that the Ser333Ala mutation decreased the activity significantly. The remaining mutants cause a partial loss of catalytic activity. All of the mutant enzymes, except Asn390Ala, were apparently correctly assembled and stable in the membrane of the R. capsulatus.

TREATMENT OF TRANSVERSE DEFICIENCY WITH SURGICALLY ASSISTED RAPID PALATAL EXPANSION IN AN OPEN BITE PATIENT SHOWING PSEUDOMACROGLOSSIA (상대적 거대설을 보이는 전치부 개방교합 환자의 외과적 급속 구개확장술을 통한 횡적 부조화의 치험례)

  • Kim, Yoon-Ji;Lee, Kyu-Hong;Park, Jun-Woo;Rhee, Gun-Joo;Cho, Hyung-Jun;Park, Yang-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.34 no.3
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    • pp.376-382
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    • 2008
  • Anterior open bite is a condition in which maxillary and mandibular incisors do not occlude at central occlusion. It is a vertical discrepancy of the jaws and dental arches that has many etiologic factors making it difficult in diagnosis, treatment and prediction of prognosis. One of the causes of open bite is abnormal size and shape of the tongue. Macroglossia, a condition in which tongue is oversized, is caused by several factors which are not clearly identifiable, and it may be a major factor of anterior and posterior open bite. Macroglossia is subdivided into true, functional and pseudomacroglossia depending on its relative size in the oral cavity. In this case report, a patient was diagnosed as skeletal Class II with pseudomacroglossia, and was treated with SARPE in order to expand the narrowed maxillary arch and Quad helix for the mandibular arch. As a result the transverse deficiency was treated. In the adult patients where no skeletal growth is expected, SARPE has shown to be effective in treating maxillomandibular transverse discrepancies in which macroglossia was accompanied as in this case.

Structure-activity relationships of cecropin-like peptides and their interactions with phospholipid membrane

  • Lee, Eunjung;Jeong, Ki-Woong;Lee, Juho;Shin, Areum;Kim, Jin-Kyoung;Lee, Juneyoung;Lee, Dong Gun;Kim, Yangmee
    • BMB Reports
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    • v.46 no.5
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    • pp.282-287
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    • 2013
  • Cecropin A and papiliocin are novel 37-residue cecropin-like antimicrobial peptides isolated from insect. We have confirmed that papiliocin possess high bacterial cell selectivity and has an ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$ and from $Ala^{25}$ to $Val^{35}$, linked by a hinge region. In this study, we demonstrated that both peptides showed high antimicrobial activities against multi-drug resistant Gram negative bacteria as well as fungi. Interactions between these cecropin-like peptides and phospholipid membrane were studied using CD, dye leakage experiments, and NMR experiments, showing that both peptides have strong permeabilizing activities against bacterial cell membranes and fungal membranes as well as $Trp^2$ and $Phe^5$ at the N-terminal helix play an important role in attracting cecropin-like peptides to the negatively charged bacterial cell membrane. Cecropin-like peptides can be potent peptide antibiotics against multi-drug resistant Gram negative bacteria and fungi.

Interaction of Cu(II)-meso-tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4) with Native and Synthetic Polynucleotides Probed by Polarized Spectroscopy

  • Lee, Mi-Jin;Lee, Gil-Jun;Lee, Dong-Jin;Kim, Seog-K.;Kim, Jong-Moon
    • Bulletin of the Korean Chemical Society
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    • v.26 no.11
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    • pp.1728-1734
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    • 2005
  • The interactions of Cu(II)-meso-Tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4), respectively referred to as o-, m- and p-CuTMPyP, and DNA, poly$[d(A-T)_2]$ and poly$[d(G-C)_2]$ were investigated by circular and linear dichroism (CD and LD). In the o-CuTMPyP case, in which the rotation of the pyridinium ring is prevented, the shape of the CD spectrum when associated to DNA and poly$[d(A-T)_2]$ resembles and is characterized by a positive band at a low drug to DNA concentration ratio (R ratio) and is bisignate at a high R ratio. The former CD spectrum shape has been attributed to porphyrin that is bound monomerically outside of DNA while the latter can be attributed to those that are stacked. When o-CuTMPyP is bound to poly$[d(G-C)_2]$, the excitonic CD appeared at a relatively high R ratio. In contrast, a characteristic negative CD band in the Soret region was apparent for both m- and p-CuTMPyP when bound to DNA and poly$[d(G-C)_2]$ at the low R ratios, indicating that the porphyrin molecule intercalates. However, the DNA is bent near the intercalation site and the plane of the porphyrin molecule tilts relative to the DNA helix axis, as judged by the magnitude of the reduced LD. Various stacking patterns were identified by the shape of the CD spectrum for m- and p-CuTMPyP when bound to poly$[d(A-T)_2]$. Three species for the former complex and two for the latter complex were found which may reflect the extent of the stacking.

Molecular Cloning of a Gene Encoding a Putative Antibacterial Peptide from Bombyx mori (누에에서 새로운 항세균성 펩타이드 유사 유전자의 분리와 염기서열 결정)

  • 김상현;제연호;윤은영;강석우;김근영;강석권
    • Korean journal of applied entomology
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    • v.35 no.4
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    • pp.321-325
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    • 1996
  • To isolate a novel gene for antibacterial peptide, an inducible clone(BmInc8) was selected by differential screening strategy from Bombyx mori cDNA library prepared from lavae injected with Escherichia coli. This clone contained a cDNA insert of 564 nucleotides and encoded 59 amino acids with an apparent molecular mass of 6.3 kDa. The cDNA sequence of BmInc8 had 61.2% identity compared to that of the bactericidin from Manduca sexta and also the deduced amino acids sequences from this insert had 65% identity compared to that of the cecropin D peptide Hyalophora cecropia. The transient expression assay of this insert using prokaryotic expression vector system revealed that the expressed peptide displayed the antibacterial activity. The cDNA sequence was deposited in GenBank under the accession number U30289.

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Institutional Arrangement and Policy Context Underlying Sustainability Actions in the U.S.: Lessons for Asian Regions

  • Hwang, Joungyoon;Song, Minsun;Cho, Seong
    • Journal of Contemporary Eastern Asia
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    • v.19 no.1
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    • pp.59-83
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    • 2020
  • This paper examines the actions and the factors driving those actions to reduce energy consumption and enhance energy efficiency taken by United States cities. While not much empirical evidence is available on why governments pursue practical sustainability actions, we attempt to shed more light on this important topic by empirically identifying factors that contribute to concrete actions toward sustainability policies. We adopt political market theory as a basic theoretical framework with policy-making applied to city energy consumption. Using the 2010 ICMA (local government sustainability policies and program) data, this study expands the focus of analyses to evaluate the effect of the form of government on energy consumption and energy efficiency by using multiple regression analysis. The findings show that at the city level, the mayor-council form of government are negatively associated with governments' efforts to reduce energy consumption. However, cities with at-large elections and municipal ownership are more likely to adopt sustainability actions. We also find that a large-scale economy has significant effects on the effort to reduce city energy consumption and improve energy efficiency. This shows that environmental policies are directly connected to locally relevant affairs, including housing, energy use, green transportation, and water. Thus, local level administrators could take an executive role to protect the environment, encourage the development of alternative energy, and reduce the use of fossil fuel and coal energy. These efforts can lead to important environmental ramifications and relevant actions by municipal governments.

East Asian Communication Technology Use and Cultural Values

  • Danowski, James A.;Park, Han Woo
    • Journal of Contemporary Eastern Asia
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    • v.19 no.1
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    • pp.43-58
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    • 2020
  • This study examines media used for information in the East Asian countries of China, Japan, South Korea, Taiwan, and Singapore, using data from the World Values Survey. The sharing of Confucian culture may lead to a uniform media structure across these nations. Another possibility is technological determinism, which would also lead to similarity across nations. However, it is possible that countries are at different stages of technology development and will eventually become more similar. An opposing notion is that differences in other values among nations predict digital media use. To examine the evidence considering these possibilities, we factor analyze each population's use of nine traditional and digital media to see how similar the structures are. What results is a three-dimensional solution for four out of five countries, except Singapore, which has a more simple two-dimensional structure. Analysts regard Singapore as the most digitally connected society, which raises the question as to whether it is higher on a technological development trajectory, to which other countries may transition. Perhaps a more simple media use structure is an adaptation to increasing information load. As well, as mobile devices have become a primary means of accessing the range of traditional and social media, it may have an expanded role in reducing media channel entropy. In terms of frequency of media use, Singapore is highest, while China is the lowest. Singapore stands out in high mobile use, and China for low Internet use. There appear to be developmental differences across the nations. Regressions on Internet use for 18 values indices find different values predictors in the East Asian countries, ruling out Confucianism as producing similar media patterns.

Preparation and Antioxidant Activities In Vitro of a Designed Antioxidant Peptide from Pinctada fucata by Recombinant Escherichia coli

  • Wu, Yanyan;Ma, Yongkai;Li, Laihao;Yang, Xianqing
    • Journal of Microbiology and Biotechnology
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    • v.28 no.1
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    • pp.1-11
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    • 2018
  • An antioxidant peptide derived from Pinctada fucata meat using an Alcalase2.4L enzymatic hydrolysis method (named AOP) and identified by LC-TOF-MS has promising clinical potential for generating cosmetic products that protect skin from sunshine. To date, there have been few published studies investigating the structure-activity relationship in these peptides. To prepare antioxidant peptides better and improve their stability, the design and expression of an antioxidant peptide from Pinctada fucata (named DSAOP) was studied. The peptide contains a common precursor of an expression vector containing an ${\alpha}$-helix tandemly linked according to the BamHI restriction sites. The DNA fragments encoding DSAOP were synthesized and subcloned into the expression vector pET-30a (+), and the peptide was expressed mostly as soluble protein in recombinant Escherichia coli. Meanwhile, the DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity of DSAOP $IC_{50}$ values were $0.136{\pm}0.006$, $0.625{\pm}0.025$, and $0.306{\pm}0.015mg/ml$, respectively, with 2-fold higher DPPH radical scavenging activity compared with chemosynthesized AOP (p < 0.05), as well as higher superoxide radical scavenging activity compared with natural AOP (p < 0.05). This preparation method was at the international advanced level. Furthermore, pilot-scale production results showed that DSAOP was expressed successfully in fermenter cultures, which indicated that the design strategy and expression methods would be useful for obtaining substantial amounts of stable peptides at low costs. These results showed that DSAOP produced with recombinant Escherichia coli could be useful in cosmetic skin care products, health foods, and pharmaceuticals.

Big Data and Knowledge Generation in Tertiary Education in the Philippines

  • Fadul, Jose A.
    • Journal of Contemporary Eastern Asia
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    • v.13 no.1
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    • pp.5-18
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    • 2014
  • This exploratory study investigates the use of a computational knowledge engine (WolframAlpha) and social networking sites (Gmail, Yahoo and Facebook) by 200 students at De La Salle-College of Saint Benilde, their "friends" and their "friends of friends" during the 2009 through 2013 school years, and how this appears to have added value in knowledge generation. The primary aim is to identify what enhances productiveness in knowledge generation in Philippine Tertiary Education. The phenomenological approach is used, therefore there are no specific research questions or hypotheses proposed in this paper. Considering that knowledge generation is a complex phenomenon, a stochastic modelling approach is also used for the investigation that was developed specifically to study un-deterministic complex systems. A list of salient features for knowledge generation is presented as a result. In addition to these features, various problem types are identified from literature. These are then integrated to provide a proposed framework of inclusive (friendly) and innovative social networks, for knowledge generation in Philippine tertiary education. Such a framework is necessarily multidisciplinary and useful for problem-solving in a globalized and pluralist reality. The implementation of this framework is illustrated in the three parts of the study: Part 1: Online lessons, discussions, and examinations in General Psychology, Introduction to Sociology, and Life and Works of Jose Rizal, for the author's students in De La Salle-College of Saint Benilde; Part 2: Facebook Report analytics of students and teachers, their friends and their friends of friends via WolframAlpha; and Part 3: Social Network Analysis of the people and groups influencing the courses' scope-and-sequence in the new General Education Curriculum for Tertiary Schools and Institutions in the Philippines.

A study on simplified procedure of enhanced designed implant drill (개선된 드릴 디자인을 적용한 간소화된 드릴링 과정에 관한 연구)

  • Yoon, Ji-Hoon;Jeon, Gye Rok;Yun, Mi-Jung;Huh, Jung-Bo;Jeong, Chang Mo
    • The Journal of the Korean dental association
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    • v.53 no.5
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    • pp.368-376
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    • 2015
  • Purpose : The objective of this research was to develop a more simplified drilling procedure with an enhanced implant drill. Materials and Methods : The drill enhanced design factors enabled implantation of Dia. 5.0mm fixture with only 2 times drilling which is more simplified drilling procedure. The enhanced drill was designed with 2 flutes, 2-phase or 3-phase formed drill tip and 25 degrees of helix angle. The proposed drilling procedure (2 times) was compared with a general drilling process (4 times) in terms of temperature changes, cutting time and ISQ value. Results : The simplified drilling procedure indicated less heat than a conventional drilling procedure (p<0.05). The enhanced drill showed significantly shorter drilling time than a conventional drill (p<0.05). On the other hand, higher insertion torque and ISQ value were observed on the the suggested drilling procedure than the conventional drilling procedure (p<0.05). Conclusion : A simplified drilling procedure with the newly designed drill could provide higher effectiveness and safety of dental implant operations under properly controlled external conditions, such as irrigation and RPM of drilling.