• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.239-246
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• 2003

We have examined the 16S-23S rRNA intergenic spacer region (ISR) of Vibrio vulnificus KCTC 2959. ISRs were amplified by primers complementary to conserved regions of 16S and 23S rRNA genes. ISR amplicons were cloned and sequenced. Analysis of the ISR sequences showed that V. vulnificus KCTC 2959 contains five types of polymorphic ISRs. Size of ISRs ranged from 424 to 741 bp in length and the number of tRNA genes ranged from one to four. The ISRs were designated as ISR-E $(tRNA^{Glu}),\;ISR-IA\;(tRNA^{Ile}-tRNA^{Ala})$, ISR-EKV $(tRNA^{Glu}-tRNA^{Lys}-tRNA^{Val})$, ISR-IAV $(tRNA^{Ile}-tRNA^{Ala}-tRNA^{val})$ and ISR-EKAV $(tRNA^{Glu}-tRNA^{Lys}-tRNA^{Ala}-tRNA^{Val})$ based on their tRNA genes. Multiple alignment of representative sequences from different Vibrio species revealed several domains of high sequence variability. We used the sequences of variable domains to design species-specific primer for detection PCR. Specificity of the primers was examined using genomic DNA prepared from 18 different Vibrio species. The results showed that the PCR using primers designed in this study can be used to detect V. vulnificus from other Vibrio species.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.312-317
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• 1988

The genes for ribosomal RNA in Rhizobium meliloti and Bradyrhizobium japonicum were analyzed by southern hybridization of BamHI, EcoRI, HindIII digested chromosomal DNA with purified 5' $^{32}P$-labeled 16S and 23S rRNA. The big differences in the hybridization pattern of both rhizobia were found. The comparative results were discussed in relation to the copy number and conservativity of restriction sites in the rRNA genes of both rhizobia.

• Korean Journal of Medicinal Crop Science
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• v.16 no.3
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• pp.195-198
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• 2008

Karyotypic analysis and FISH (fluorescence in situ hybridization) with 45S and 5S rRNA genes were carried out in Persicaria tinctoria H Gross. The somatic metaphase chromosomes were ranged from 2.25 ${\mu}m$ to 1.50 ${\mu}m$ in length. Chromosome number was 2n = 4x = 40 with the basic number of x = 10. The chromosome complement of the species consisted of 16 pairs of metacentrics (chromososomes 1,2,3,4,6,7,8,9, 10, 11, 12, 13, 15, 18, 19 and 20) and 4 pairs of submetacentrics (chromosome 5, 14, 16 and 17). The karyotype formula was K(2n) = 4x = 32 m + 8 sm. In FISH analysis, three pairs of 45S rRNA gene loci on the terminal region of submetacentrics (chromosomes 5, 16 and 17) and two pairs of 5S rRNA gene loci on the centromeric region of metacentrics (chromosomes 9 and 11) were detected, respectively.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.112-121
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• 2017

Edwardsiella tarda is a gram-negative pathogenic bacterium in aquaculture that can cause hemorrhagic septicemia in fish. Many secreted proteins have already been identified as virulent factors of E. tarda. Moreover, since virulent phenotypes are based on the expression regulation of virulent genes, understanding the expression profile of virulent genes is important. A quantitative RT-PCR is one of the preferred methods for determining different gene expressions. However, this requires the selection of a stable reference gene in E. tarda, which has not yet been systematically studied. Accordingly, this study evaluated nine candidate reference genes (recA, uup, rpoB, rho, topA, gyrA, groEL, rpoD, and 16S rRNA) using the Excel-based programs BestKeeper, GeNorm, and NormFinder under different culture conditions. The results showed that 16S rRNA was more stable than the other genes at different culture growth phases. However, at the same culture time, topA was identified as the reference gene under the conditions of different strains, different culture media, and infection, whereas gyrA was identified under the condition of different temperatures. Thus, in experiments, the expression of gapA and fbaA in E. tarda was analyzed by RT-qPCR using 16S rRNA, recA, and uup as the reference genes. The results showed that 16S rRNA was the most suitable reference gene in this analysis, and that using unsuitable reference genes resulted in inaccurate results.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.352-359
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• 2022

Recently, with the development of genetic technology, interest in environmental DNA (eDNA) to study biodiversity according to molecular biological approaches is increasing. Environmental DNA has many advantages over traditional research methods for biological communities distributed in the environment but highly depends on the established base sequence database. This study conducted a comprehensive analysis of the habitat status and classification at the genus level, which is mainly used in eDNA (12S rRNA, 16S rRNA, 18S rRNA, COI, and CYTB), focusing on Korean registration taxon groups (phytoplankton, zooplankton, macroinvertebrates, and fish). As a result, phytoplankton and zooplankton showed the highest taxa proportion in 18S rRNA, and macroinvertebrates observed the highest ratio in the nucleotide sequence database in COI. In fish, all genes except 18S rRNA showed a high taxon ratio. Based on the Korean registration taxon group, the gene construction of the top 20 genera according to bio density observed that most of the phytoplankton were registered in 18S rRNA, and the most significant number of COI nucleotide sequences were established in macroinvertebrates. In addition, it was confirmed that there is a nucleotide sequence for the top 20 genera in 12S rRNA, 16S rRNA, and CYTB in fish. These results provided comprehensive information on the genes suitable for eDNA research for each taxon group.

• Journal of Life Science
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• v.22 no.2
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• pp.167-176
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• 2012

Three protease-producing halophilic bacteria were isolated from fermenting anchovy. Isolated FAM 10, FAM 114, and FAM 115 were found to grow optimally at salt concentrations of 2-4%, 10%, and 6%, respectively, and could grow in salinity of up to 18-22%. The salinity conditions for optimum protease production were 6% in FAM 10 and 10% in FAM 114 and FAM 115. The protease activity of FAM 10 was gradually inhibited by the addition of NaCl up to 10%, and was not evident at 14%, whereas FAM 114 and FAM 115 displayed protease activity at 14% NaCl and could not be measured at 18%. These results demonstrated that the three isolated strains belong to protease-producing, moderately halophilic bacteria. Strain FAM 10, FAM 114, and FAM 115 were identified as Salinivibrio sp., Halobacillus sp., and Halobacillus sp. respectively, based on comparative analyses of the 16S rRNA gene and the 16S-23S intergenic space sequence (IGS), biochemical testing, and Gram staining. Salinivibrio sp. FAM 10 had two 16S rDNAs containing different sequences at position 191 and four IGSs that harbored no tRNA gene and tRNA genes for isoleucine, alanine, glutamate, lysine, and/or valine. Halobacillus sp. FAM 114 and FAM 115 had completely identical 16S rRNA gene sequences and showed 99% identity to the sequences of various Halobacillus strains. The three IGSs found in the genome of both strains displayed 99% sequence identity with Halobacillus aidingensis and Halobacillus sp. JM-Hb, and had $IGS^0$ with no tRNA gene and $IGS^{IA}$ with tRNA genes for isoleucine and alanine.

• Ocean Science Journal
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• v.41 no.4
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• pp.315-318
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• 2006

Three Synechococcus strains were isolated from seawater near the Ieodo Ocean Research Station (IORS), and their 16S rDNA genes and the internal transcribed spacer (ITS) between the 16S and 23S rRNA genes were sequenced to investigate their phylogenetic relationships. Phylogenetic trees based on the 16S rDNA and ITS sequences showed that they clustered in the main MC-A Synechococcus group (subcluster 5.1), but formed branches differentiating them from the described clades. As the IORS is located in an area affected by diverse water masses, high Synechococcus diversity is expected in the area. Therefore, the IORS might be a good site to study the diversity, physiology, and distribution of the Synechococcus group.

• Journal of fish pathology
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• v.22 no.3
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• pp.391-400
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• 2009

Genetic identification of 17 fish-derived Aeromonas strains was attempted using 5 housekeeping genes. 16S rRNA, gyrB, rpoD, dnaJ and recA genes from the 17 strains were amplified, and total of 85 amplicons were sequenced. DNA sequences of the strains and type strains of the 17 Aeromonas homology groups were used for genetic identification and phylogenetic analyses. None of the strains was identified as a single species using the 16S rRNA gene, showing the same identities (average = 99.7%) with several Aeromonas species. According to gyrB, rpoD, dnaJ, and recA, 9 strains and RFAS-1 used in this study were identified as A. hydrophila and A. salmonicida, respectively. However, the other strains were closely related to 2 or more Aeromonas species (i.e., A. salmonicida, A. veronii, A. jandaei, A. media and A. troda) depending on the genetic marker used. In this study, gyrB, rpoD, dnaJ and recA gene sequences proved to be advantageous over 16S rRNA for the identification of field Aeromonas isolates obtained from fish. However, there are discrepancies between analyses of different phylogenetic markers, indicating there are still difficulties in genetic identification of the genus Aeromonas using the housekeeping genes used in this study. Advantages and disadvantages of each housekeeping gene should be taken into account when the gene is used for identification of Aeromonas species.

• Biomedical Science Letters
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• v.10 no.4
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• pp.333-339
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• 2004

A multiplex PCR assay targeting the yst and 16S rRNA genes of Yersinia enterocolitica was developed to specifically identify pathogenic Y. enterocolitica from pure culture. Simultaneous amplification of 145 and 416 bp fragments of the yst and 16S rRNA genes of Y. enterocolitica was obtained using the primer pairs in a single reaction. Validation of the assay was performed with the reference Yersinia strains and other members of the family Enterobacteriaceae. The defined primer pairs amplified the targeted sequence from only pathogenic Y. enterocolitica strains, whereas none of the other bacterial species yielded any amplified fragments. Within an assay time of 4 h, this assay offers a very specific, reliable, and inexpensive alternative to the conventional phenotypic assays used in clinical laboratories to identify pathogenic Y. enterocolitica.