• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.577-583
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• 1994

To classify Lactobacillus casei strains on the basis of difference in their chromosomal DNA sequence, we have performed polymerase chain reactions on their chromosomal DNA by using random primers, and followed by analyzing randomly amplified polymorphic DNA fragments. We also developed a mini-preparative method to isolate PCR-grade chromosomal DNA from Lacto- bacillus casei strains within 3 hours. Based on RAPD pattems by polymerase chain reactions with degenerated random primers, 4 Lactobacillus casei strains and 2 mutant strains were successfully discriminated. Results were very sensitive, strain-specific and reproducible. It was also reliable. These results suggest that RAPD may be applied efficiently for the identification of several Lactoba- cillus casei strains.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.1-10
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• 2008

Nucleic scids transfer the genetic information for serving a central biological purpose. The nucleic acids are polymers of nucleotides and they are mainly ribonucleic acid(RNA) and deoxyribonucleic acid(DNA). The nucleotides are stoichiometrically composed of five-carbon sugars, nitrogeneous bases, and phosphoric acids. The chemistry of nucleic acids and characteristics of different genomes are decribed for further study. Most of DNA genomes tend to be circular including bacterial genomes and eukaryotic mitochondrial DNA. Eukaryotic chromosomes in cells, in contrast, are generally linear. The ends of linear chromosomes are called telomeres. The genomes of different species, such as mammals, plants, invertebrates can be compared with the chromosome ends. The telomeric complex allows cells to distinguish the random DNA breaks and natural chromosomal ends. The very ends of chromosomes cannot be replicated by any ordinary mechanisms. The shortening of telomeric DNA templates in semiconservative replication is occurred with each cell division. The short telomere length is critically related to aging, tumors and dieases.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.171-171
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• 1993

발암물질의 조기검색법을 개발하고자 변이원성 물질의 스크리닝법으로 널리 사용되고 있는 Ames test 및 chromosomal aberration test를 본 연구에서 개발하고자 하는 DNA 및 Protein-adduct 형성시험법과 비교 연구하였다. 벤조피렌과 아플라톡신 B$_1$을 모델 발암물질로 하여 실시한 Ames test에서는 두 화합물 모두 양성을 나타냈으나 용량-반응 관계가 뚜렷하지 않았다. 또한 고농도에서는 시험물질의 독성체 의해 정상적인 Ames test의 수행이 어려됐다. Chromosomal aberration test에서도 Ames test와 비슷한 결과를 나타냈으며 특히 고농도에서 시험을 실시했을 경우 Ames test에서와 마찬가지로 세포독성의 현상이 관찰되었다. 그러나 본 연구에서 새로이 개발한 DNA 및 Protein-adduct형성 시험법은 저농도에서 고농도에 이르기까지 뚜렷한 용량-반응 관계를 나타냈으며 Ames test 및 chromosomal test에서 일어날 수 있는 false positive나 false negative의 결과를 가져다 줄 우려가 없다. 또한 시험시간이 1-2시간 정도 소요되므로 기존의 방법보다 시험시간을 약 40배 가량 단축시킬 수 있었다.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.94-107
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• 2005

Prenatal diagnosis (PND) such as amniocentesis or chorionic villi sampling has been widely used in order to prevent the birth of babies with defects especially in families with single gene disorderor chromosomal abnormalities. Preimplantation genetic diagnosis (PGD) has already become an alternative to traditional PND. Indications for PGD have expanded beyond those practices in PND (chromosomal abnormalities, single gene defects), such as late-onset diseases with genetic predisposition, and HLA typing for stem cell transplantation to affected sibling. After in vitro fertilization, the biopsied blastomere from the embryo is analyzed for single gene defect or chromosomal abnormality. The unaffected embryos are selected for transfer to the uterine cavity. Therefore, PGD has an advantage over PND as it can avoid the risk of pregnancy termination. In this review, PGD will be introduced and application of PGD in inborn error metabolic disorder will be discussed.

• Journal of Plant Biology
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• v.38 no.4
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• pp.321-328
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• 1995

Calli obtained from basal disc explants of Allium victorialis var.platyphyllum wre grown in three kinds of nutrient media (MS, BDS, and B5), and the frequencies of mitotic index and the chromosomal aberrations were analysed. The mitotic index varied from 0.55% to 1.01% with respect to culture media and ages. The mitotic irregularities like micro-, bi- and multi-nuclei, chromosome bridge and laggards were noted in each types of calli. The chromosome number variations observed in metaphase stage were identified aneuploid and tetraploid. Structural variations such as dicentric chromosomes, centromere breakage and small chromosomes were observed. Relationship between basal medium and chromosomal variability was not observed in this study. But, in BDS medium, NAA and BA had a more effect on number variation than kinetin.

• Animal cells and systems
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• v.2 no.3
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• pp.351-353
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• 1998

A 245 bp segment of E. coli chromosomal replication origin, oriC, contains 11 repeats of the GATC sequence in which adenine is methylated by Dam methylase. Newly replicated oriC is hemimethylated. The parental strand of the newly replicated oriC is methylated, but the nascent strand is not yet methylated until methylated by Dam methylase. The hemimethylated oriC plays an important role in the regulation of chromosomal replication. Activity in the seqA mutant was identified to bind preferentially to hemimethylated DNA, but not to fully-methylated DNA. This activity may participate in the sequestration of initiation of chromosomal replication.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.248-254
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• 2000

(R)-JG-381, a R form of alkylglycidic acid derivative, was examined for mutagenicity in the reverse mutation test on bacteria, chromosomal aberration test on cultured mammalian cells and micronucleus test in mice. In the reverse mutation test on bacteria using Salmonella typhimurium strain TA98, TA100, TA102, TA1535, TA1537 with or without a metabolic activation system (S9 mix), (R)-JG-381 did not affect the revertant colonies but significantly increased revertant colonies in one test strain, TA98, compared with the vehicle control. In the chromosomal aberration (CA) test using cultured Chinese Hamster Lung fibroblast(CHL) cells, the number of aberrant cells was clot increased in the presence or absence of 59 mix at concentration of the (R)-JG-381 0.025 $\mu$l/m1 to 0.1 $\mu$l/m1, compared with vehicle control. In the micronucleus (MN) test, micronucleated polychromatic erythrocytes in the (R)-JG-381-treated mice were not different from those of the vehicle-treated mice.

• Journal of Genetic Medicine
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• v.15 no.2
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• pp.49-54
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• 2018

Nuchal translucency is an important indicator of an aneuploid fetus in prenatal diagnostics. Previously, only the presence of aneuploid could be confirmed by conventional karyotyping of fetuses with thick nuchal translucency. With the development of genetic diagnostic techniques, however, it has been reported that subtle variations not detectable by conventional karyo-typing might occur in cases of pathologic clinical syndrome in euploid fetuses. One of the newer, high-resolution genetic methods in the prenatal setting is chromosomal microarray. The possible association between nuchal translucency thickness with normal karyotype and submicroscopic chromosomal abnormalities detectable by microarray has been studied. How and when to apply microarray in clinical practice, however, is still debated. This article reviews the current studies on the clinical application of microarray in cases of increased nuchal translucency with normal karyotype for prenatal diagnosis.

• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.25-32
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• 1993

The nodular hyperplasia of the thyroid is a common thyriod disease. Nodular hyperplasia does rarely progress to thyroid cancer. The differentiation of a nodular hyperplasia from a neoplasm may be simple or difficult, both clinically and anatomically. The papillary carcinoma of the thyroid is the most common type of thyroid malignancies. There were few studies about cytogenetic observation in thyroid cancer. But only one case of banding observation in nodular hyperplasia have been reported. In order to compare the chromosomal changes in the thyroid cancer and the noncancerous thyroid disease, we performed cytogenetic analysis in two papillary carcinoma and two nodular hyperplasia after cell culture. The chromosomal pattern of the nodular hyperplasia found was very heterogenous but no clonal abnormaly in both cases was observed. Case I : A modal chromosomal number was in 42-46 range. Chromosome 8, 19, 21. 22 were commonly lost. 9 structural anomalities among 51 analysed cells were observed but they were not clonal. Case II: A modal chromosomal number was 43. Chromosome 17 and 19 were commonly lossed. Common cytogenetic characters of this two nodular hyperplasia are hypodiploidity and very heterogenous chromosomal pattern. The result about the papillary carcinoma are as follow. In one case some numerical and structural chromosomal changes were observed. But they were not clonal abnormality. In another case the chromosomal pattern found was very heterogenous with a clonal abnormality of del(11)(q23). The modal number was 46. The del(11)(q23) a chromosomal change in papillary carcinoma of the thyroid have previously been reported(Eva Olah et al. 1989). We suggest that 11q deletion may be important role to pathogenesis of papillary carcinoma of the thyroid. According to this results, we could not find out specific differences about chromosomal changes and any relationship between the papillary carcinoma and the nodular hyperplasia.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.104-110
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• 2004

To determine evolution and genotype of new chromosomal AmpC $\beta$-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, sequencing, and phy-logenetic analysis using developed expression/secretion vector. Six isolates have shown to produce AmpC $\beta$-lactamases. Six genes of AmpC $\beta$-lactamases that are responsible for the resistance to cephamycins (cefoxitin and cefotetan), amoxicillin, cephalothin, and amoxicillin-clavulanic acid were cloned and characterized in pMSG12119. Insert fragment containing the ampC genes was sequenced and found to have an open reading frame coding for 381-amino-acid $\beta$-lactamase. The nucleotide sequence of four ampC genes ($bla_EcloK992004.l$, $bla_EcloK995120.1$, $bla_EcloK99230$, and $bla_EareK9911729$) shared considerable homology with that of chromosomal ampC gene ($bla_EcloMHN1$) of E. cloacae MHN1 (more than 99.6% identity). The sequences of two ampC genes ($bla_EcloK9973$ and $bla_EcloK9914325$) showed close similarity to the chromosomal ampC gene ($bla_EcloQ908R$) of E. clo-acae 908R (99.7% identity). The results from phylogenetic analysis suggested that six ampC genes could be originated from $bla_EcloMHN1$ / or $bla_EcloQ908R$ / MIC patterns and exact pI values of six transformants indicated that the developed expression/secretion vector (pMSG1219) was suitable for the characterization of foreign genes in E. coli strain.