• English Language & Literature Teaching
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• v.16 no.4
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• pp.201-222
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• 2010

The purpose of this study is to investigate /l/-deletion in lC clusters which are composed of a lateral followed by consonants at syllable-final position in English. For this, I have analyzed /l/-deletion in words depending on conditions and theoretical analyses such as Sonority Sequencing Generalization, Cluster Simplification, Complex sounds and merger, and Feature Geometry, but they didn't offer a very satisfactory explanation to the phenomenon. Therefore, I adopted a historical approach in order to determine the cause and origin of /l/-deletion in lC clusters, and then as a phonological analysis tool, I relied on the constraints and their ranking in Optimal Theory framework for explaining /l/-deletion in the clusters more consistently. As a result, I can explain the phenomenon more explicitly than from the above mentioned analyses.

• Journal of Veterinary Science
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• v.21 no.6
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• pp.88.1-88.13
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• 2020

Background: Listeria monocytogenes is a gram-positive bacterium that causes listeriosis mainly in immunocompromised hosts. It can also cause foodborne outbreaks and has the ability to adapt to various environments. Peptide uptake in gram-positive bacteria is enabled by oligopeptide permeases (Opp) in a process that depends on ATP hydrolysis by OppD and F. Previously a putative protein Lmo2193 was predicted to be OppD, but little is known about the role of OppD in major processes of L. monocytogenes, such as growth, virulence, and biofilm formation. Objectives: To determine whether the virulence traits of L. monocytogenes are related to OppD. Methods: In this study, Lmo2193 gene deletion and complementation strains of L. monocytogenes were generated and compared with a wild-type strain for the following: adhesiveness, invasion ability, intracellular survival, proliferation, 50% lethal dose (LD₅₀) to mice, and the amount bacteria in the mouse liver, spleen, and brain. Results: The results showed that virulence of the deletion strain was 1.34 and 0.5 orders of magnitude higher than that of the wild-type and complementation strains, respectively. The function of Lmo2193 was predicted and verified as OppD from the ATPase superfamily. Deletion of lmo2193 affected the normal growth of L. monocytogenes, reduced its virulence in cells and mice, and affected its ability to form biofilms. Conclusions: Deletion of the oligopeptide transporter Lmo2193 decreases the virulence of L. monocytogenes. These effects may be related to OppD's function, which provides a new perspective on the regulation of oligopeptide transporters in L. monocytogenes.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1338-1346
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• 2006

Ansamitocin P-3 is a potent antitumor agent produced by A. pretiosum. A deletion mutant of A. pretiosum was constructed by deleting the asm2 gene, a putative transcriptional repressor. The deletion mutant showed a 9-fold enhanced ansamitocin P-3 productivity. The response surface method with central composite design was employed to further optimize the culture medium composition for ansamitocin P-3 production by the deletion mutant. The concentrations of four medium ingredients, dextrin, maltose, cotton seed flour, and yeast extract, which have been reported as major components for ansamitocin production, were optimized through a series of flask culture experiments. The optimum concentrations of the selected factors were found to be dextrin 6.0%; maltose 3.0%; cotton seed flour 0.53%; and yeast extract 0.45%. The maximum titer of ansamitocin P-3 was 78.3 mg/l with the optimized composition, about 15-folds higher than the unoptimized titer of 5.0 mg/l obtained with YMG medium.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.233-239
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• 2010

Four genes (yqfR, yfmL, ydbR, deaD) were identified as putative DEAD-box RNA helicase genes in the genomic sequence of Bacillus subtilis by homology search. To understand the function of these genes, each of the genes was deleted and the constructed strains were tested for their growth charateristics at different temperatures. The growth rate of ydbR deletion mutant ($T_d$=53 min) was a little bit reduced at $37^{\circ}C$ as compared to that of wild type strain (CU1065). But the growth rate of other three (yqfR, yfmL, deaD) deletion mutants ($T_d$=30-40 min) is nearly equal to the growth rate of wild type ($T_d$=32 min). On the other hands, the growth rate of deletion mutants were reduced at $22^{\circ}C$ in order of yqfR ($T_d$=151 min), yfmL ($T_d$=214 min), ydbR ($T_d$=343 min), which showed cold-sensitive phenotype. The deletion mutant of deaD ($T_d$=109 min) grew equally as compared to the growth rate ($T_d$=102 min) of the wild type at $22^{\circ}C$ and did not show cold-sensitive growth. Double, triple and quadruple deletion mutants of these genes were constructed, and growth rate of these mutants were measured at various temperature conditions ($22^{\circ}C$, $37^{\circ}C$, $42^{\circ}C$) using LB broth. Multiple deletion mutations showed more severe cold-sensitive growth than single deletion mutations, and double deletion of ydbR and yfmL ($T_d$=984 min) showed most cold-sensitive growth than any other double mutants. Such a cold-sensitive growth of these mutations is quite similar to the result of csdA or srmB deletion in E. coli and suggested that physiological role of ydbR and yfmL is related with ribosome assembly.

• Phonetics and Speech Sciences
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• v.8 no.4
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• pp.9-14
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• 2016

This study investigated the patterns of coda deletion in spontaneous Seoul Korean speech. More specifically, the current study focused on three factors in promoting coda deletion, namely, word position, consonant type, and morpheme type. The results revealed that, first, coda deletion frequently occurred when affixes were attached to the ends of words, rather than in affixes in word-internal positions or in roots. Second, alveolar consonants [n] and [l] in the coda positions of high-frequency affixes [nɨn] and [lɨl] were most likely to be deleted. Additionally, regarding affix reduction in the word-final position, all subjects seemed to depend on this articulatory strategy to a similar degree. In sum, the current study found that affixes without primary semantic content in spontaneous speech tend to undergo the process of reduction, favoring the occurrence of specific pronunciation variants.

• Journal of English Language & Literature
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• v.56 no.5
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• pp.851-870
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• 2010

The purpose of this paper is to investigate the distribution of /ju/ in British English, especially after the coronal sonorants /n, l, /r/. The sequence /ju/ is related with vowels such as /u/, /ʊ/, and /ʊ/, and has occasioned a variety of conflicting analyses or suggestions. One of those is in which context /j/ is deleted if we suppose that the underlying form is /ju/. The context differs according to the dialect we deal with. In British English, it is known that /j/ is deleted always after /r/, and usually after /l/ when it occurs in an unstressed word-medial syllable. To check this well-known fact I searched OED Online (the 2nd Edition, 1989) for those words which contain /n, l, r/ + /ju, jʊ, u, ʊ, (j)u, (j)ʊ/ in their pronunciations, using the search engine provided by OED Online. After removing some unnecessary words, I classified the collected words into several groups according to the preceding sonorant consonants, the positions, and the presence (or absence) of the stress, of the syllable where /ju/ occurs. The results are as follows: 1) the deletion of /j/ depends on the sonorant consonant which /ju/ follows, the position where it occurs, and the presence of the stress which /ju/ bears; 2) though the influence of the sonorant consonants is strong, the position and stress also have non-trivial effect on the deletion of /j/, that is, the word-initial syllable and the stressed syllable prefer the deletion of /j/, and word-medial and unstressed syllable usually retain /j/; 3) the stress and position factors play their own roles even in the context where the effect of /n, l, r/ is dominant.

• English Language & Literature Teaching
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• v.11 no.1
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• pp.137-154
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• 2005

The purpose of this paper is to analyze vowel lengthening triggered by resyllabification. In general, short vowels become long when a following consonant is deleted, as shown in stehli 'steel' > st$\bar{e}$li and *fimf 'five' > five. We can account for the phenomenon in a straightforward way within the framework of CV phonology (Clements & Keyser, 1983) : deletion of a coda consonant C slot and then the preceding vowel spreads onto it, resulting in a long vowel. The analysis, however, cannot hold for words like ealhes 'temple', where deletion of an onset segment eventually triggers vowel lengthening in the preceding syllable. In order to account for this, I propose resyllabification. That is, ealhes first becomes eales by /h/-deletion. Next, the /l/ in coda is resyllabified as the onset of the following syllable, leaving its C slot unoccupied. Finally, the vowel spreads onto the empty slot, producing a long vowel.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1288-1298
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• 2019

Bacterial ATP synthases drive ATP synthesis by a rotary mechanism, and play a vital role in physiology and cell metabolism. Corynebacterium glutamicum is well known as an industrial workhorse for amino acid production, and its ATP synthase operon contains eight structural genes and two adjacent genes, cg1360 and cg1361. So far, the physiological functions of Cg1360 (GenBank CAF19908) and Cg1361 (GenBank CAF19909) remain unclear. Here, we showed that Cg1360 was a hydrophobic protein with four transmembrane helices (TMHs), while no TMH was found in Cg1361. Deletion of cg1360, but not cg1361, led to significantly reduced cell growth using glucose and acetic acid as carbon sources, reduced F1 portions in the membrane, reduced ATP-driven proton-pumping activity and ATPase activity, suggesting that Cg1360 plays an important role in ATP synthase function. The intracellular ATP concentration in the ${\Delta}cg1360$ mutant was decreased to 72% of the wild type, while the NADH and NADPH levels in the ${\Delta}cg1360$ mutant were increased by 29% and 26%, respectively. However, the ${\Delta}cg1361$ mutant exhibited comparable intracellular ATP, NADH and NADPH levels with the wild-type strain. Moreover, the effect of cg1360 deletion on L-valine production was examined in the L-valine-producing V-10 strain. The final production of L-valine in the $V-10-{\Delta}cg1360$ mutant reached $9.2{\pm}0.3g/l$ in shake flasks, which was 14% higher than that of the V-10 strain. Thus, Cg1360 can be used as an effective engineering target by altering energy metabolism for the enhancement of amino acid production in C. glutamicum.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.9-17
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• 2018

To investigate the role of bkdR, sigL, yplP, and des genes which were known to be involved in fatty acid synthesis and sensitive at low temperature, deletion mutants of Bacillus subtilis CU1065 and JH642 were constructed. To determine the low temperature sensitivity of these genes, we compared the growth curves of cells at $37^{\circ}C$ and $15^{\circ}C$. At $37^{\circ}C$, wild type and deletion mutants showed almost similar growth but only bkdR deletion strain at $15^{\circ}C$ showed very slow growing compared with wild type. At $15^{\circ}C$ sigL and yplP deletions were somewhat slower or similar to those of wild type strain. Double and triple mutants for bkdR, sigL, yplP deletions were constructed and grown at $20^{\circ}C$ in LB agar to investigate cold sensitive growth. Double or triple deletions including bkdR deletion showed cold sensitive growing. In order to identify more clearly cold sensitive growth, the experiments were carried out under cold shock conditions in which the temperature was lowered from $37^{\circ}C$ to $15^{\circ}C$ at the point of 0.4 optical densities at 600 nm. In these cold shock experiments, only bkdR deletion showed significantly lower growing and additional des deletion increases cold sensitivity. The bkdR activates the bkd operon, which catabolized isoleucine, valine and leucine, amino acids and produce precursors for the synthesis of branched fatty acids. At cold shock growing of bkdR deletion strain, isoleucine recovered cold sensitivity of bkdR deletion but valine did not restore cold sensitivity. Isoleucine is used as a precursor for the synthesis of anteiso-branched fatty acids. On the other hand, valine is used as a precursor for the synthesis of iso-branched fatty acids. This indicates that anteiso-branched fatty acid plays an important role at the cold shock condition.

• Korean Linguistics
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• v.72
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• pp.257-282
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• 2016

The aim of this paper is to research phonological and morphological features in Korean Voices from Berlin. The Korean Voices from Berlin was recorded in 1917 at Berlin by 5 Korean prisoners engaged in World War I, some of them came from North Hamgyeong Province, the others came from Pyeongan Province, therefore these data show a North Korean regional dialect. The data are composed of three materials, counting numbers, reciting scriptures and singing folksongs. The results of this research are as follows. 1) The consonant system of Korean voices is similar to standard Korean. The 19 consonants are classified according to 5 manners of articulations and 5 points of articulations. 2) The liquid /l/ has three allophones, [ɾ] appeared in an onset position, [l] in a word medial coda position or preceded by [l], [ɹ] in a word final coda position. 3) The vowel system of Korean voices is similar to early 20th Korean's. It has 8 monophthongs, /a, ʌ, o, u, ɯ, i, e, ${\varepsilon}$/. 4) The 1 to 10 numbers in Korean voices are similar to Middle-Korean numerals. 5) The genitive particle '/ɯi/의' is pronounced [i], [ɯ], [${\varepsilon}$], especially [ɯ] is appeared in Sino Korean. 6) The /l/-deletion of conjugations are similar to Middle-Korean, /l/ deletion always occurred, if [+cor] consonants are followed.