• Journal of Microbiology
• /
• v.45 no.2
• /
• pp.105-112
• /
• 2007

The objective of this study was to analyze the phylogenetic composition of bacterial community in the soil of an earth-cave (Niu Cave) using a culture-independent molecular approach. 16S rRNA genes were amplified directly from soil DNA with universally conserved and Bacteria-specific rRNA gene primers and cloned. The clone library was screened by restriction fragment length polymorphism (RFLP), and representative rRNA gene sequences were determined. A total of 115 bacterial sequence types were found in 190 analyzed clones. Phylogenetic sequence analyses revealed novel 16S rRNA gene sequence types and a high diversity of putative bacterial community. Members of these bacteria included Proteobacteria (42.6%), Acidobacteria (18.6%), Planctomycetes (9.0 %), Chloroflexi (Green nonsulfur bacteria, 7.5%), Bacteroidetes (2.1%), Gemmatimonadetes (2.7%), Nitrospirae (8.0%), Actinobacteria (High G+C Gram-positive bacteria, 6.4%) and candidate divisions (including the OP3, GN08, and SBR1093, 3.2%). Thirty-five clones were affiliated with bacteria that were related to nitrogen, sulfur, iron or manganese cycles. The comparison of the present data with the data obtained previously from caves based on 16S rRNA gene analysis revealed similarities in the bacterial community components, especially in the high abundance of Proteobacteria and Acidobacteria. Furthermore, this study provided the novel evidence for presence of Gemmatimonadetes, Nitrosomonadales, Oceanospirillales, and Rubrobacterales in a karstic hypogean environment.

• Journal of Animal Science and Technology
• /
• v.45 no.3
• /
• pp.473-482
• /
• 2003

In vivo protective and in vitro inhibitory activities of Lactobacillus casei YIT 9018. against typical enteritis causing Salmonella enteritidis KU101 and IgA level after challenge have been determined. In order to identify the strains of lactobacilli the sequences of 16S-23S rRNA intergenic spacer region were determined. All the test strains of Lactobacillus spp. inhibited Salmonella enteritidis, the intensity varied depending upon the species of lactobacilli. Effects on the survival rate of the mouse after challenge with Salmonella enteritidis KU101 on feeding Lactobacillus spp. have shown the highest survival rate in L. helveticus CU 631 followed by L. casei YIT 9018 and L. johnsonii C-4 and the lowest in control mice. The higher level of total Ig A concentration in the intestinal fluid of lactobacilli fed mice than control mice was observed. The sequences of 16S-23S rRNA intergenic spacer region of seven strains of Lactobacillus casei could be utilized as a strain identification, those sequences showed some degree of difference in homology.

• The Journal of Natural Sciences
• /
• v.14 no.1
• /
• pp.39-50
• /
• 2004

T7 RNA polymerase is a single subunit RNA polymerase able to accomplish whole transcription process without auxiliary factors. In order to study transcription elongation mechanism of phage T7 RNA polymerse, stepwise walking of RNA polymerase was established by immobilizing biotinylated DNA template with streptavidin bead, series of active and stable elongation complexes were obtained, Transcripts were radio isotope labeled at the 16thm 17th and 18th nucleotide residues so stable elongation transcription complex of T7 RNA polymerase containing 22-40 nucleotide residues could be identified. We identified the positions of stablely formed transcription elongation complexes of termination site in intrinsic hairpin-independent PTH terminator sequence through the established stepwise walking of wild-type of mutant R173C T7 RNA polymerases. The results suggest that stable elongation transcription complexes were at the site of passing PTH terminator signal by mutant R173C RNA polymerase.

• Journal of Microbiology
• /
• v.44 no.6
• /
• pp.694-698
• /
• 2006

Several marine bacterial strains were isolated from Undaria pinnatifida (Miyok in Korean). Sixty-six strains were isolated on R2A agar media at $10^{\circ}C$ and identified by a phylogenetic analysis of the 16S rRNA gene sequences. They were grouped into 10 different sequence types based on the initial sequence analysis of the 5' domain of the gene (approximately 500 bp). Full sequences of 16S rRNA gene, were obtained from one strain in each sequence type and the species-affiliation was determined using phylogenetic and sequence similarity analyses. The results of the analyses indicated that they were closely related to Psychrobacter aquimaris, P. celer, P. nivimaris, P. pulmonis, Psychromonas arctica or Bacillus psychrodurans. These bacteria are marine or psychrotrophic bacteria. Because the sporophytes of U. pinnatifida are cultured on the costal area during winter, the U. pinnatifida-associated bacteria appeared to grow at low temperatures. U. pinnatifida sporophytes can be a good source for the isolation of psychrotrophic bacteria.

• Research in Plant Disease
• /
• v.29 no.1
• /
• pp.94-99
• /
• 2023

Blueberry red ringspot virus (BRRSV) and blueberry scorch virus (BlScV) are included in the quarantine virus list managed by the Korean Animal and Plant Quarantine Agency. A multiplex polymerase chain reaction (PCR) assay with an internal control was developed for the simultaneous detection of both viruses. The specific primers used here were designed based on the highly conserved regions of the genomic sequences of each virus, obtained from the National Center for Biotechnology Information nucleotide databases. The primers were designed to amplify a partial sequence within coat protein (CP) for detecting BRRSV and a partial sequence within the CP-16 kDa for detecting BlScV. 18S ribosomal RNA (rRNA) was used as internal control, and the primer set used in a previous study was modified in this study for detecting 18S rRNA. Each conventional PCR using the BRRSV, BlScV, and 18S rRNA primers exhibited a sensitivity of approximately 1 fg plasmid DNA. The multiplex PCR assay using the BRRSV, BlScV, and 18S rRNA primers was effective in simultaneously detecting the two viruses and 18S rRNA with a sensitivity of 1 fg plasmid DNA, similar to that of conventional PCR assays. The multiplex PCR assay developed in this study was performed using 14 blueberry cultivars grown in South Korea. BRRSV and BlScV were not detected, but 18S rRNA was all detected in all the plants tested. Therefore, our optimized multiplex PCR assay could simultaneously detect the two viruses and 18S rRNA in field samples collected from South Korea in a time-efficient manner. This approach could be valuable in crop protection and plant quarantine management.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.5
• /
• pp.1100-1105
• /
• 2005

Previous work has identified a Streptomyces coelicolor gene, rns, encoding a 140 kDa protein (RNase ES) that exhibits the endoribonucleolytic cleavage specificity characteristic of RNase E and confers viability on and allows the propagation of E. coli cells lacking RNase E. Here, we identify a putative S. coelicolor 9S rRNA sequence and sites cleaved by RNase ES. The cleavage of the S. coelicolor 9S rRNA transcript by RNase ES resulted in a 5S rRNA precursor (p5S) that had four and two additional nucleotides at the 5' end and 3' ends of the mature 5S rRNA, respectively. However, despite the similarities between RNase E and RNase ES, these enzymes could accurately process 9S rRNA from just their own bacteria, indicating that these ancient enzymes and the rRNA segments that they attack appear to have co-evolved.

• Korean Journal of Microbiology
• /
• v.48 no.2
• /
• pp.79-86
• /
• 2012

ErmSF is one of the Erm family proteins which catalyze S-adenosyl-$_L$-methionine dependent modification of a specific adenine residue (A2058, E. coli numbering) in bacterial 23S rRNA, thereby conferring resistance to clinically important macrolide, lincosamide and streptogramin B ($MLS_B$) antibiotics. $^{222}FXPXPXVXS^{230}$ (ErmSF numbering) sequence appears to be a consensus sequence among the Erm family. This sequence was supposed to be involved in direct interaction with the target adenine from the structural studies of Erm protein ErmC'. But in DNA methyltarnsferase M. Taq I, this interaction have been identified biochemically and from the complex structure with substrate. Arginine 223 and 227 in this sequence are not conserved among Erm proteins, but because of the basic nature of residues, it was expected to interact with RNA substrates. Two amino acid residues were replaced with Ala by site-directed mutagenesis. Two mutant proteins still maintained its activity in vivo and resistant to the antibiotic erythromycin. Compared to the wild-type ErmSF, R223A and R227A proteins retained about 50% and 88% of activity in vitro, respectively. Even though those arginine residues are not essential in the catalytic step, with their positive charge they may play an important role for RNA binding.

• Journal of fish pathology
• /
• v.6 no.2
• /
• pp.93-101
• /
• 1993

The RNAI mutation of Saccharomyces cerevisia is a recessive and temperature sensitive lethal mutation which interferes with the production of mRNA, rRNA, and tRNA. However, the precise role of RNAI gene have not been revealed until yet. We have cloned rna1-1 mutant gene from rna1-1 mutant yeast strain(R49 ; trpl, ura3-52, rna1-1). The 3.4kb BglII fragment of wild type RNAI clone(81-2-6) contains whole RNAI gene. The genomic southern blotting with BglII digested R49 genomic DNA as a probe shows the unique and identical band with wild type 3.4kb BglII fragment. Therefore, We prepared partial BglII genomic library(3~4kb BglII fragments) into BamH I site of pUC19. The rna 1-1 mutant clone was screened with Digoxigenin(DIG)-lableled probe by high density colony hybridization. The 5'-flanking region of rna1-1 gene was sequenced by dideoxy chain termination method. The 5'-flanking sequence of RNAI gene contains three TATA-like sequence ; TAATA, TATA and TTTTAA at position of -67, -45, and -36 from first ATG codon respectively. The 5'-flanking region of wild type RNA I gene from ATG codon to -103nt was deleted with Bal31 exonuclease digestion, generating $pUC{\Delta}$/RNA I. After constructing $pYEP{\Delta}RNA$ I (consists of -103nt deleting RNA I gene, URA3 gene, $2{\mu}m$ rep. origin), pYEPrna1-1(consists of Xba I fragment of pUCrna1-1. URA3 gene, $2{\mu}m$ rep. origin), and pYEPRNAI. each plasmid was transformed into host strain(trpl, ura3-52, rna1-1) by electroporation, respectively. Yeast transformant carrying $pYEP{\Delta}RNA$ I did not complement the thermal sensitivity of rna1-1 gene. It means that TATA-like sequences in 5'-flanking region is not TATA sequence for transcribing RNAI gene and there may be other essential sequence in upstream region for the transcription of RNAI gene.

• Korean Journal of Microbiology
• /
• v.55 no.3
• /
• pp.303-305
• /
• 2019

An actinobacterial strain designated Gordonia sp. MMS17-SY073 (=KCTC 49257) was isolated from a coastal soil of an island, and its complete genome was analyzed. A single contig consisting of 5,962,176 bp with the G + C content of 67.4% was obtained, and the annotation resulted in 5,201 protein-coding genes, 6 rRNA genes and 45 tRNA genes. Strain MMS17-SY073 was closest to the type strain of Gordonia soli based on the 16S rRNA gene sequence comparison, sharing 98.5% sequence similarity. A number of biosynthetic gene clusters for secondary metabolites, non-ribosomal peptide synthetase types in particular, could be identified from the genome.

• Animal Systematics, Evolution and Diversity
• /
• no.nspc3
• /
• pp.139-146
• /
• 1992

The primary sequence of the 18S rRNA gene of a crustacean Pugettia quadridens (Decapoda: Pleocyemata: Brachyura) was determined by the PCR cloning and Taq sequencing. The 18S rRNA gene of this species in 1837 bases long, and 46 bases shorter than that of another crustacean decapod Oedignathus inermis. The similarity between two species is 90.8% when the insertion and/or deletion sites were excluded. Within the molecule, the most conservative (identical) region locates at the position of 1137-1206 and it is 70 bases long. The most long consecutive nucleotide differences occur at the position between 46-55 and the second most between 399-407. The sequence variation in the primary structure of 18S rRNA gene are not evenly distributed throughout the molecule.