• Journal of Aquaculture
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• v.10 no.4
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• pp.403-407
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• 1997

Intraspecific sequence variation was detected by polymerase chain reaction (PCR) and direct sequencing of a 350-nucleotide region of the mitochondrial 12S rRNA gene of two natural populations (Han River and Nakdong River) and one hatchery stock (Jinhae Inland Fisheries Institute) of local strain common carp, one Israeli strain of common carp stock from Pukyong National University (PKU), and one hybrid between Israeli strain of common carp female and local strain common carp male from PKU stock. There is little variation in 350 bases of the mitochondrial 12S rRNA gene sequences among 2 natural and 1 hatchery local strain common carp populatins, representing abut 7 to 20 nucleotide differences (less than 6%). The sequence of specimens from Han River was more similar to that from Nakdong River (identity=98.0%) than to that from Jinhae Inland Fisheries Institute (identity=96.3%). Sequence variation between Israeli strain and wild local strain common carp was higher than the variation within natural stocks. The level of variation was ranged from 15.7 to 17.7%. The hybrid showed very similar nucleotide4 sequence of 12S rRNA gene to the sequence of Israeli strain with the identity of 98.9%.

• Animal cells and systems
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• v.3 no.3
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• pp.275-283
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• 1999

Korean R. plancyi occupies a restricted area in western South Korea and shows a relatively low level of genic variability (%P＝15.2, Ho=0.052, He＝0.048). In contrast, R. nigromaculata is broadly distributed in South Korea. The observed low level of variability of R. nigromaculata (%P＝14.3, Ho＝0.042, He＝0.043) is probably due to its recent colonization. Populations of R. nigromaculata exhibited considerable genetic differentiation (F$_{sT}$=0.149) and low level of gene flow (Nm＝1.427) among populations, compared to those of R. Plancyi (F$_{sTF$_{sT}$}$=0.096, Nm＝2.354), which occupies a restricted area. The observed levels of gene flow among populations of R. nigromaculata (Nm＝1.427) over a broad geographic range is relatively higher than other amphibian species. The high level of gene flow is probably the result of the high dispersal abilities of R. nigromaculata. A survey of temporal genic variation of R. nigromaculata showed that there was no significant change on the overall average genetic diversity from 1978 (average He＝0.044) to 1997 (average He＝0.040). Wright's F-statistics also indicated no significant genetic differentiation from 1978 (F$_{sT}$＝0.118) to 1997 (F$_{sT}$＝0.108). This suggests that the environmental change appears to have had little influence on the genetic composition of R. nigromaculata in the study areas during the past 20 years. The low level of temporal variation might be due to the result of high dispersal abilities and wide migration range of this species.

• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.581-598
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• 1997

This paper is concerned with the impulsive control problem $$ \dot{x}(t) = f(t, x) + g(t, x)\dot{u}(t), t \in [0, T], x(0) = \overline{x}, $$ where u is a possibly discontinuous control function of bounded variation, $f : R \times R^n \mapsto R^n$ is a bounded and Lipschitz continuous function, and $g : R \times R^n \mapsto R^n$ is continuously differentiable w.r.t. the variable x and satisfies $\mid$g(t,\cdot) - g(s,\cdot)$\mid$ \leq \phi(t) - \phi(s)$, for some increasing function $\phi$ and every s < t. We show that the map $u \mapsto x_u$ is Lipschitz continuous when u ranges in the set of step functions whose total variations are uniformly bounded, where $x_u$ is the solution of the impulsive control system corresponding to u. We also define the generalized solution of the impulsive control system corresponding to a measurable control functin of bounded variation.

• Animal Systematics, Evolution and Diversity
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• v.37 no.3
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• pp.235-241
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• 2021

To provide better taxonomic information of the genus Nectoneanthes, the two DNA barcode regions of mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal DNA (rDNA) sequences of Nectoneanthes oxypoda and N. uchiwa were determined. In addition, the respective sequences of four nereidid species closely related to Nectoneanthes were retrieved from GenBank for comparison and to estimate intra- and inter-specific genetic distances. The aligned sequence lengths of COI and 16S rDNA were 570 bp and 419 bp long, respectively. The mean intraspecific variation in both markers was less than 1% in all species except for that in COI of H. diadroma (1.87%). The mean interspecific variation between N. oxypoda and N. uchiwa was 12.02% regarding COI and 1.85% regarding 16S rDNA. In contrast, the mean interspecific variation between species of other genera was comparably higher(i.e., genus Perinereis: 20.5% in COI and 8.3% in 16S rDNA; genus Hediste: 13.18% in COI and 2.64% in 16S rDNA), compared with that between the two Nectoneanthes species. This result indicated that these Nectoneanthes species are genetically more closely related than other congeneric species of different genera. The DNA barcoding information on Nectoneanthes species generated in this study provides valuable insights for further biodiversity studies on nereidid species.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.50-55
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• 1997

1992년부터 1995년까지 약 4개년 동안 전남 지역에서 사육하고 있는 가축의 유병률을 조사한 결과, 유방염으로 의심이 되는 젖소 970두 중에서 180두(18.6%)가 유방염에 이환되었으며, 돼지 2,400두 중에서 84두(3.5%)가 설사증에 이환되었고, 닭 1,010수중에서 9수(0.9%)가 설사증에 이환되었다. 대장균의 분리율을 조사한결과, 유방염에 이환되어 있는 젖소 180두중 37두(20.6%)에서 대장균이 분리되었으며, 설사증에 이환되어 있는 돼지 84두중 51두(60.7%)에서 대장균이 분리되었고, 설사증에 이환되어 있는 닭 9수중 5수(55.6%)에서 대장균이 분리되었다. Acriflavine을 이용하여 대장균의 S-R변이를 조사한 결과, S-R변이는 mercuric chloride, cysteine, caffeine, glucose, nicotine 등의 순으로 나타났는데, 이중 mercuric chloride가 가장 감수성이 높았다. 대장균의 항균요법제에 대한 감수성은 naxcel, linsmycin, cephalexin, gentamycin등이 높은 감수성을 나타내었는데, S-R변이 후에는 감수성이 일반적으로 저하되는 경향이었다.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.2
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• pp.97-103
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• 2001

Acriflavine 시험법을 이용해서 수종의 화학물질을 첨가한 배지에 대장균과 Clostridium perfringens을 배양하여 변이를 유도한 후, S-R 변이와 변이 후의 항생제에 대한 감수성을 조사한 결과, 화학물질에 대한 S-R변이의 경우, 대장균은 mercuric chloride, cysteine, caffeine, glucose, nicotine 등의 순으로 나타났고, C. perfringens는 mercuric chloride, nicotine, caffeine, cystein, glucose 등의 순으로 나타났으며 양자 공히 mercuric chloride가 가장 감수성이 높았다. 항생제에 대한 S-R 변이 후의 감수성은 대장균과 C. perfingens가 공히 S-R변이 후에는 감수성이 일반적으로 저하되는 경향이었다.

• Animal cells and systems
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• v.4 no.1
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• pp.77-85
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• 2000

This study has demonstrated the molecular variation of 5S rRNA genes in 15 Allium subgenus Rhizirideum and 1 Allium subg. Allium. For cloning of the 5S rRNA genes, PCR products were obtained from amplification with oligonucleotide primers which were derived from the conserved coding region of 5S rRNA genes. These amplified PCR products were cloned and identified by FISH and sequence analysis. The 5S rRNA loci were primarily located on chromosomes 5 and/or 7 in diploid species and various chromosomes in alloploid species. The size of the coding region of 5S rRNA genes was 120 bp in all the species and the sequences were highly conserved within Allium species. The sizes of nontranscribed spacer (NTS) region were varied from 194 bp (A. dektiude-fustykisum, 2n=16) to 483 bp (A. sativum). Two kinds of NTS regions were observed in A. victorialis var. platyphyllum a diploid, A. wakegi an amphihaploid, A. sacculiferum, A. grayi, A. deltoide-fistulosum and A. wenescens all allotetraploids, while most diploid species showed only one NTS region. The species containing two components of NTS region were grouped with different diploid species in a phylogenetic tree analysis using the sequences of 5S rRNA genes and adjacent non-coding regions.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.166-173
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• 1997

1993년부터 1995년까지 약 3개년 동안 우리 나라에서 사육하고 있는 가축의 유병율을 조사한 결과, 닭 16,200수 중에서 54수(0.3%)가 괴사성 장염에 이환 되었으며 새끼돼지 620두 중에서 9두(13.8%)가 장독혈증에 이환 되었다. C. perfringens의 분리율을 조사한 결과, 괴사성 장염에 이환 되어있는 닭 54수 중 7수(13.0%)에서 본균이 분리되었으며 장독혈증에 이환 되어있는 새끼돼지 66두 중 14두(21.2%)에서 본균이 분리되었고 장독혈증에 이환 되어있는 소 9두 중 3두(33.3%)에서 본균이 분리되었다. Acriflavine을 이용하여 C. perfringens의 S-R변이를 조사한 결과, S-R변이는 mercuric chloride, nicotine, caffeine, cysteine, glucose 등의 순으로 나타났는데, 이중 mercuric chloride가 가장 감수성이 높았다. C. perfringens의 항균요법제에 대한 감수성은 cepalothin, penicillin, erythromycin, amikacin 등이 높은 감수성을 나타내었는데, S-R변이 후에는 감수성이 일반적으로 저하되는 경향이었다. 중화시험법을 이용하여 C. perfringens의 독소형을 분류한 결과, cd 24균주 중 22균주(91.7%)는 A형이었으며 2균주(8.3%)는 C형이었다.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.78-86
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• 2006

We examined the genetic diversity in intra-populations of Korean shiner, Coreoleuciscus splendidus, in six major rivers (Bukhan, Namhan, Geum, Osipcheon, Nakdong and Seomjin river) of Korea based on two different mitochondrial genes, the mitochondrial cytochrome b and the 16S rRNA. Analysis of sequence variation in a 657-bp segment of the mitochondrial cytochrome b gene revealed deep divergence among populations (98.2~99.9%) and high genetic diversity from geographically isolated populations. Intra-specific variation in this 697-bp segment of the 16S rRNA gene sequences was very low and nearly identical. Six isolate populations of C. splendidus showed a high similarity (97.7%~99.7%). This result may be indicative of a complex history of connection and isolation of the rivers in the Korea peninsula.

• Bulletin of the Korean Mathematical Society
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• v.37 no.2
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• pp.229-247
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• 2000

This paper is concerned with the impulsive Cauchy problem where the control function u is a possibly discontinuous vector-valued function with finite total variation. We assume that the vector fields f, $g_i$(i=1,…, m) are dependent on the time variable. The impulsive Cauchy problem is of the form x(t)=f(t,x) +$\SUMg_i(t,x)u_i(t)$, $t\in$[0,T], x(0)=$\in\; R^n$, where the vector fields f, $g_i$ : $\mathbb{R}\; \times\; \mathbb{R}\; \longrightarrow\; \mathbb(R)^n$ are measurable in t and Lipschitz continuous in x, If $g_i's$ satisfy a condition that $\SUM{\mid}g_i(t_2,x){\mid}{\leq}{\phi}$ $\forallt_1\; <\; t-2,x\; {\epsilon}\;\mathbb{R}^n$ for some increasing function $\phi$, then the imput-output function can be continuously extended to measurable functions of bounded variation.