• Journal of Life Science
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• v.16 no.1
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• pp.71-75
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• 2006

We analyzed the phylogenic relationships of 23 partial 18S rDNA sequences of 22 species (1 species has 2 strains) belonging to Sarcorptiforms include 4 new sequences, using several tools. Although geographic distributions are quite far from, sequence similarity of two strains of Dermatophygoides pteronyssinus isolated from Japan and New Zealand were very high. This result suggests that mite migration by animals including human occurred in the two continents. We investigated the Endeostigmata taxonomic relationship between the Prostigmata and Oribatida subgroups using small fragments (340-400 bp) of their 185 rDNA sequences. But Endeostigmata was not grouped with Oribatida or Prostigmata. In conclusion, it is first reported phylogenic relationship for classified mites included in Sarcoptiformes using 185 rDNA sequence analysis and its system is a very powerful tool for classification of mites.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.266-274
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• 2000

Understanding of microbial community structure in soil-root system is necessary to use beneficial soil and rhizosphere microbes for improvement of crop production and biocontrol. The knowledge of behavior and function of microbes in soil-root system plays a key role for the application of beneficial inocula. Because the majority of the intact bacteria in soil are unable to grow on nutrient media, both culturable and nonculturable bacteria have to be studied together. In our study, culture-independent survey of bacterial community in the soil-root system of red pepper fields was conducted by the sequence analysis of three universal clone libraries of genes which code for small-subunit rRNA (rDNA). Universal small subunit rRNA primers were used to amplify DNA extracted from each sample and PCR products were cloned into pGEM-T. Out of 27 clones sequenced, 25 clones were from domain bacteria. Two of the rDNA sequences were derived from eukaryotic organelles. Within the domain bacteria, several kingdoms were represented : the Proteobacteria (16 clones). Cytophyga-Flexibacter-Bacteroides group (2 clones). the high G+C content gram-positive group(1 clone) and 4 unknown clones.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.370-372
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• 1995

A Phaffia rhodozyma chromosomal fragment (approximately 3.8 kb) capable of functioning as an origin for the replication of a kanamycin resistance ($Km^r$) plasmid in S. cerevisiae was isolated by the use of origin search plasmid, pHN134. In S. cerevisiae, transformation frequencies using the plasmid pHN134 containing an autonomously replicating sequence of P. rhodozyma was 450-580 CFU/$\mu g$ DNA. The stability of the recombinant plasmid were 16-19$\%$.

• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1743-1750
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• 2007

Two Gram-negative, nonmotile, coccobacilli, SW-$3^T$ and SW-$100^T$, were isolated from sea water of the Yellow Sea in Korea. Strains SW-$3^T$ and SW-$100^T$ contained ubiquinone-9 (Q-9) as the predominant respiratory lipoquinone and $C_{18:1}\;{\omega}9c$ and $C_{16:0}$ as the major fatty acids. The DNA G+C contents of strains SW-$3^T$ and SW- $100^T$ were 44.1 mol% and 41.9 mol%, respectively. A neighbor-joining tree based on l6S rRNA gene sequences showed that the two isolates fell within the evolutionary radiation enclosed by the genus Acinetobacter. Strains SW-$3^T$ and SW-$100^T$ exhibited a l6S rRNA gene similarity value of 95.7% and a mean DNA-DNA relatedness level of 9.2%. Strain SW-$3^T$ exhibited l6S rRNA gene sequence similarity levels of 93.5-96.9% to the validly described Acinetobacter species and fifteen Acinetobacter genomic species. Strain SW-$100^T$ exhibited l6S rRNA gene sequence similarity levels of less than 97.0% to the other Acinetobacter species except Acinetobacter towneri DSM $14962^T$ (98.0% similarity). Strains SW-$3^T$ and SW-$100^T$ exhibited mean levels of DNA-DNA relatedness of 7.3-l6.7% to the type strains of some phylogenetically related Acinetobacter species. On the basis of phenotypic, phylogenetic, and genetic data, strains SW-$3^T$ and SW-$100^T$ were classified in the genus Acinetobacter as two distinct novel species, for which the names Acinetobacter marinus sp. novo (type strain SW-$3^T$=KCTC $12259^T$=DSM $16312^T$) and Acinetobacter seohaensis sp. novo (type strain SW-$100^T$=KCTC $12260^T$=DSM $16313^T$) are proposed, respectively.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.243-249
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• 2017

An agar-degrading bacterium, designated as the GNUM08123 strain, was isolated from samples of red algae collected from the Yongil Bay near East Sea, Korea. The isolated GNUM08123 strain was gram-negative, aerobic, motile, and beige-pigmented, with $C_{16:0}$ (25.9%) and summed feature 3 (comprising $C_{16:1}{\omega}7c/iso-C_{15:0}2-OH$, 34.4%) as its major cellular fatty acids. A similarity search based on the 16S rRNA gene sequence revealed that it belonged to class Gammaproteobacteria and shared 97.7% similarity with the type strain Vibrio chagasii $R-3712^T$. The DNA G+C content of strain $GNUM08123^T$ was 46.9 mol%. The major isoprenoid quinone was ubiquinone-8. The results of DNA-DNA relatedness and 16S rRNA sequence similarity analyses, in addition to its phenotypic and chemotaxonomic characteristics, suggest that strain GNUM08123 is a novel species within genus Vibrio, designated as Vibrio sp. GNUM08123. Agarase production by strain GNUM08123 was induced by agar and sucrose, but was repressed probably owing to carbon catabolite repression by glucose and maltose.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.449-460
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• 2022

This study was performed to reveal phenotypic characters and identity of symbiont bacteria of Nasutitermes as well as investigate their potential as antagonist of plant pathogenic fungi. Isolation of the symbiont bacteria was carried out from inside the heads and the bodies of soldier and worker termite which were collected from 3 locations of nests. Identification was performed using phenotypic test and sequence of 16S ribosomal DNA (16S rDNA). Antagonistic capability was investigated in the laboratory against 3 phytopathogenic fungi i.e., Phytophthora capsici, Ganoderma boninense, and Rigidoporus microporus. Totally, 39 bacterial isolates were obtained from inside the heads and the bodies of Nasutitermes. All the isolates showed capability to inhibit growth of P. capsici, however, 34 isolates showed capability to inhibit growth of G. boninense and 32 isolates showed capability to inhibit growth of R. microporus. Two bacterial strains (IK3.1P and 1B1.2P) which showed the highest percentage of inhibition were further identified based on their sequence of 16S rDNA. The result showed that 1K3.1P strain was placed in the group of type strain and reference strains of Lysinibacillus fusiformis meanwhile 1B1.2P strain was grouped within type strain and reference strains Paenibacillus alvei. The result of this study supply valuable information on the role of symbiont bacteria of Nasutitermes, which may support the development of the control method of the three above-mentioned phytopathogenic fungi.

• Journal of Microbiology
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• v.39 no.1
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• pp.11-16
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• 2001

Tentative identification of Leuconostoc lactis IH23 isolated from kimchi (a fermented vegetable product) has been described previously with 16S rDNA sequencing (Choi, 1., M. Sc. Thesis Inha Univ.1999). This strain produced the slime identified as dextran based on IR, $\^$13/C- and $^1$H-NMR spectroscopic results. Further study proved that the isolate IH23 belongs to a homogeneous genetic group with L. lactis DSM 20202$\^$T/ and L. argentinum DSM 8581$\^$T/. The results showed DNA-DNA homology of 99-100%, 16S rDNA gene sequence similarity (97.7% ), and a phylogenetic relationship although L. argentinum DSM 8581$\^$T/ had lower homology (80-91%). These data indicate that L. argentinum DSM 8581$\^$T/ and the isolate IH23 belong to an identical species with L. lactis DSM 20202$\^$T/at the genetic level, although in carbohydrate fermentation, the isolate IH23 was mast closely related to L. argentinum DSM 8581$\^$T/ and quite different from L. lactis DSM 20202$\^$T/. Here we first report the isolation of consistent phenotypic variation in Leuconostoc lactis. We also emphasize that the nomenclature of subspecies needs to be differentiated into the three strains mentioned above in Leuconostoc lactis.

• International Journal of Oral Biology
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• v.46 no.3
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• pp.140-145
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• 2021

This study aimed to develop Lautropia mirabilis-specific quantitative real-time polymerase chain reaction (qPCR) primers based on the sequence of DNA-directed RNA polymerase subunit beta gene. The PrimerSelect program was used in designing of the qPCR primers, RTLam-F4 and RTLam-R3. The specificity of the qPCR primers were performed by conventional PCR with 37 strains of 37 oral bacterial species, including L. mirabilis. The sensitivity of the primers was determined by qPCR with the serial dilution of purified genomic DNA of L. mirabilis KCOM 3484, ranged from 4 ng to 4 fg. The data showed that the qPCR primers could detect only L. mirabilis strains and as little as 40 fg of genome DNA of L. mirabilis KCOM 3484. These results indicate that this qPCR primer pair (RTLam-F4/RTLam-R3) may be useful for species-specific detection of L. mirabilis in epidemiological studies of oral bacterial infectious diseases such as periodontal disease.

• Journal of Microbiology
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• v.44 no.3
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• pp.263-268
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• 2006

Pleurotus ostreatus is a widely cultivated white-rot fungus. Owing to its considerable enzymatic versatility p. ostreatus has become the focus of increasing attention for its possible utility in biobleaching and bioremediation applications. Interactions between microorganisms can be an important factor in those processes. In this study, we describe the presence of a bacterial species associated with P. ostreatus strain G2. This bacterial species grew slowly (approximately 30 days) in the liquid and semi-solid media tested. When p. ostreatus was inoculated in solid media containing Tween 80 or Tween 20, bacterial microcolonies were detected proximal to the fungal colonies, and the relevant bacterium was identified via the analysis of a partial 16S rDNA sequence; it was determined to belong to the Burkholderia cepacia complex, but was not closely related to other fungus-isolated Burkholderiaceae. New specific primers were designed, and confirmed the presence of in vitro P. ostreatus cultures. This is the first time that a bacterial species belonging to the B. cepacia complex has been found associated with P. ostreatus.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.48-52
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• 2005

Six stains of plant growth promoting rhizobacteria were selected through germinating seed assay and root colonization assay. Among them, SKU-78 strain induced significant suppression of bacterial wilt disease in tomato and pepper plants. Seed treatment followed by soil drench application with this strain resulted in over 60% reduction of bacterial wilt disease compared with the control. It was suggested that SKU-78 strain activated the host defense systems in plants, based on lack of direct antibiosis against pathogen. According to Bergey's Manual of Systemic Bacteriology and 16S rDNA sequence data, SKU-78 stain was identified as Bacillus sp. SKU-78.