• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.651-655
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• 2000

Polymerase chain reaction (PCR) was used to specifically detect Phytophthora infestans by analyzing the sequences of the ribosomal internal transcribed spacer regions (ITS) in the rDNA of the Phytophthora species. Based on the sequence data, PISP-1 together with the ITS3 primer were used to detect p. infestans. A single ca. 450 bp segment was observed in P. infestans, but not in the other fungal or bacterial isolates. Two factors, the annealing temperature and template DNA quantity, were investigated to determine the optimal conditions. Using these species-specific primers, a unique band was obtained within annealing temperatures of $55^{\circ}C$-$61^{\circ}C$ and template DNA levels of 10 pg-100 ng.

• Molecules and Cells
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• v.19 no.2
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• pp.283-288
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• 2005

Complete 18S rDNA sequences were determined for 10 vetigastropods in order to investigate the phylogeny of Vetigastropoda, which is controversial. These sequences were analyzed together with published sequences for nine other vetigastropods and two nerites. With the two nerites as outgroups, the phylogeny was inferred by three analytical methods, neighbor-joining, maximum likelihood, and maximum parsimony. The 18S rDNA sequence data support the monophyly of four vetigastropod superfamilies, the Pleurotomarioidea, the Fissurelloidea, the Haliotoidea, and the Trochoidea. The present results yield the new branching order: (Pleurotomarioidea (Fissurelloidea ((Scissurelloidea, Lepetodriloidea) (Haliotoidea, Trochoidea)))) within the vetigastropod clade.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.985-992
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• 2007

The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.236-242
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• 2003

A culture-independent and -dependent survey of the bacterial community structure in the rhizosphere and soil samples from hot pepper plants was conducted using 16S rDNA clone library and FAME analyses. Out of the 78 clones sequenced, 56% belonged to Proteobacteria, 4% to high G+C Gram- positive group, 3% to Cytophyga-Flexibacter-Bacreroides, and 32% could not be grouped with any known taxonomic division. Among the 127 FAME isolates identified, 66% belonged to low G+C Gram-positive bacteria (Baciilus spp.) and 26% to high G+C Gram-positive bacteria. In a cluster analysis, the results for both methods were found to be strikingly dissimilar. The current study is the first comparative study of FAME and 165 rDNA clonal analyses performed on the same set of soil, rhizosphere soil, and root samples.

• Mycobiology
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• v.28 no.1
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• pp.17-26
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• 2000

The orchid symbiotic fungi were isolated from the roots of Korean native orchid (Cymbidium goeringii) collected and Chinese orchid (C. sinense) obtained from greenhouses. They were identified as a species of Rhizoctonia, based on the sequences of 18r rDNA, the microscopic observations of mycelia, and the symbiotic relationships with commercial orchids. The isolate collected from Chinese orchids was revealed to be a species of Ceratobasidium endophytica, and to be different from the other isolates at the thickness of the mycelia stained in the root cells of Korean native orchids. The other isolates collected from the Korean native orchids were considered to be a species of Tulsanella repens (anamorphic: Epulorhiza repens) or its related one. The physiologic or microscopic variations were oftenly observed among them, but the tendency of grouping these in the 18s rDNA sequences were observed to be consistent with those of the localities collected. The further taxonomical segregating for Korean symbiotic fungi was not made because the information concerned were limited in this moment, but was recognized as based on the sequences of 18s DNA.

• Animal cells and systems
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• v.4 no.3
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• pp.257-261
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• 2000

To elucidate phylogenetic relationships among poecilostome families 18S rDNA sequence data were generated for seven poecilostome and one cyclopoid copopods by PCR cloning and sequencing techmiques. Phylogenetic trees were constructed by maximum parsimony, neighbor joining, and maximum likelihood methods using cyclopoid sequence as an outgroup. The results from three different analyses showed that the seven poecilostome families were eiridel into two groups: Clausidiidae-Myicolidae-Synaptiphillidae-bomolochidae and Lichomologidae-Chondracanthidae-Ergasilidae. The molecular phylogenies were consistent with those from the morphological characters. Therefore, these analyses porvide further evidence for the utility of 18S rDNA sequences in addressing phylogenetic relationships among poecilostome families.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.577-609
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• 1995

Bacteria have been regarded as one of the most important factors in pulpal and periapical diseases. Streptococci are frequently isolated facultative anaerobes in infected root canals. Recently molecular biological techniques have been rapidly progressed. This study was designed to apply the molecular biological tools to the identification and classification of streptococci in the endodontic microbiology. Streptococci isolated from infected root canals were identified with both Vitek Systems and API 20 STREP. Identification results were somewhat different in several strains of streptococci. Eighteen streptococci and enterococcal was difficult so to digest plasmid DNA using Hind III and EcoRI to differentiate strains by restriction enzyme analysis of plasmid DNA. 16S rDNA of chromosome was amplified by polymerase chain reaction(PCR) and then restricition fragment length polymorphism(RFLP) using several restriction enzymes was observed. The molecular mass of 16S rDNA of chromosomal DNA was approximately 1.4kb. There were three to five RFLP patterns using eight restriction enzymes. RFLP patterns digested with CfoI which recognizes four base sequences were identical in all stains. Hind III which recognizes six base sequences could not digest the 16S rDNA. Restriction enzymes which recognize five base sequences were suitable for RFLP pattern analysis. At least three different restriction enzymes were needed to compare each strains. 16S rDNA PCR-RFLP was simple and rapid to differentiate and classify strains and could be used in the epidemiological study of root canal infections.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.123-129
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• 2021

Polyhydroxyalkanoate (PHA) synthase is a key enzyme for PHA production in microorganisms. The class IV PHA synthase is composed of two subunits: PhaC and PhaR. The PhaR subunit, which encodes the phaR gene, is only present in class IV PHA synthases. Therefore, the phaR gene is used as a biomarker for bacteria that contain a class IV PHA synthase, such as some Bacillus spp. The phaR gene was developed to screen phaR-containing Bacillus spp. The phaR screening method involved two steps: phaR gene amplification by PCR and phaR amplicon detection using a DNA lateral flow assay. The screening method has a high specificity for phaR-containing Bacillus spp. The lowest amount of genomic DNA of B. thuringiensis ATCC 10792 that the phaR screening method could detect was 10 pg. This novel screening method improves the specificity and sensitivity of phaR gene screening and reduces the time and cost of the screening process, which could enhance the opportunity to discover good candidate PHA producers. Nevertheless, the screening method can certainly be used as a tool to screen phaR-containing Bacillus spp. from environmental samples.

• Korean Journal of Plant Taxonomy
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• v.39 no.3
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• pp.193-198
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• 2009

Chromosome analysis using karyotyping and bicolor FISH were carried out for two Maackia species (M. fauriei and M. amurensis) found in Korea. The somatic metaphase chromosome number was 2n = 2x = 18 in both, and the size of these chromosomes ranged from 3.58 to $5.82{\mu}m$. The chromosome complements consisted of two pairs of metacentric (chromosomes 1 and 7), four pairs of submetacentrics (chromosomes 4, 6, 8 and 9) and three pairs of subtelocentrics (chromosomes 2, 3 and 5) in M. fauriei but, chromosomes 4 (subtelocentric) and 7 (submetacentric) of M. amurensis have different morphology. Using bicolor FISH, a pair of 45S rDNA loci were observed for both M. fauriei and M. amurensis, but the number and site of the 5S rDNA signal were different in the two species. M. fauriei has two pairs of 5S signals on chromosomes 7 and 8 but, M. amurensis has four paris on chromosomes 3, 4, 7 and 7. Hence, the 5S rDNA is a useful FISH for Maackia species.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.622-627
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• 2002

Diphtheria toxin repressor (DtxR) binds to approximately 30 to 35-bp regions containing an interrupted 9-bp inverted repeat within a 19-bp core sequence. The core sequence is fairly conserved and critical for DtxR binding. The flanking regions that are consisted of 5 to 8 more of nucleotides from the core are also required for DtxR binding. The nucleotides in both flanking regions are A-T rich. To examine whether the A-T nucleotides in both flanking regions from the core have significant roles for DtxR binding, a DNA fragment was constructed based on the diphtheria tox promoter/operator, and DNA fragments with substitution of A and T nucleotides In the flanking regions to G and C were also constructed. To assess the effect of these substitutions on binding of DtxR and repressibility by DtxR, $\beta$-galactosidase activity from lacZ fused to the region was assessed. Gel mobility shift of the region by purified DtxR was also examined. The DNA fragments containing the mutations in the flanking regions still exhibited repression and mobility shift with DtxR. The core segment with the mutation is still, therefore, recognized by DtxR. Nonetheless, the results from the assays indicated that the substitution significantly decreased repression of the operator by DtxR in vivo under high-iron condition and decreased binding of DtxR to the operator. These results suggest that A and T nucleotides fur both flanking regions are preferred for the binding of DtxR.