• Journal of Species Research
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• v.10 no.3
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• pp.191-200
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• 2021

To study the biodiversity of bacterial species, here we report indigenous prokaryotic species of Korea. A total of 23 bacterial strains affiliated to the class Alphaproteobacteria were isolated from various environmental sources including seaweeds, seawater, fresh water, wetland/marsh, tidal sediment, plant roots, sewage and soil. Considering higher than 98.8% 16S rRNA gene sequence similarities and formation of a well-defined phylogenetic clade with named species, it was confirmed that each strain belonged to the predefined bacterial species of the class Alphaproteobacteria. There is no official report of these 23 species in Korea; 20 species of 16 genera (Mameliella, Yangia, Paracoccus, Ruegeria, Loktanella, Phaeobacter, Dinoroseobacter, Tropicimonas, Lutimaribacter, Litoreibacter, Sulfitobacter, Roseivivax, Labrenzia, Hyphomonas, Maricaulis, Thalassospira) in the order Rhodobacterales and 3 species of a single genus (Brevundimonas) in the order Caulobacterales. Gram-staining, cell morphology, basic biochemical characteristics, isolation sources, optimum temperature, growth media, and strain IDs are detailed in the species description as well as Table 1.

• Journal of Species Research
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• v.10 no.4
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• pp.321-335
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• 2021

In 2020, a total of 12 bacterial strains were isolated from soil after a comprehensive investigation of indigenous prokaryotic species in Korea. It was determined that each strain belonged to independent and predefined bacterial species, with high 16S rRNA gene sequence similarity (>98.7%) and formation of a robust phylogenetic clade with the closest species. This study identified four families in the phylum Actinobacteria, two families in the phylum Proteobacteria, one family in the phylum Bacteroidetes one family in the phylum Firmicutes; and four species in the family Nocardiaceae, two species in the family Nocardioidaceae, one species in the family Cellulomonadaceae, one species in the family Hymenobacter, one species in the family Methylobacteriaceae, one species in the family Microbacteriaceae, one species in the family Bacillaceae and one species in the family Sphingomonadaceae. There is no official report of these 12 species in Korea, so they are described as unreported bacterial species in Korea in this study. Gram reaction, basic biochemical characteristics, colony, and cell morphology are included in the species description section.

• Journal of Species Research
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• v.12 no.spc2
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• pp.1-6
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• 2023

During an investigation into the indigenous prokaryotic species diversity in Korea, a total of five bacterial strains were isolated from various environments in Korea. The isolated bacterial strains were identified by analyzing their 16S rRNA gene sequences, and those with a minimum of 98.7% sequence similarity with known bacterial species but not reported in Korea were designated as unrecorded species. These isolates were assigned to three phyla, five orders, five families, and five different genera. The isolates were identified as Cumulibacter manganitolerans (99.1%) and Myolicibacterium tusciae (98.7%) of the class Actinomycetes; Bacillus marasmi (99.9%) of the class Bacilli; and Novosphingobium mathurense (100%) and Microvirga ossetica (98.8%) of the class Alphaproteobacteria. Gram reaction, colony and cellular morphology, basic biochemical characteristics, and phylogenetic position of theses isolates are also described.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.693-699
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• 2001

An intracellular levansucrase gene, lscR from Rahnella aquatilis ATCC 15552, was cloned and its nucleotide sequence was determined. Nucleotide sequence analysis of this gene revealed a 1,238 bp open reading frame coding for a protein of 415 amino acids. The levansucrase was expressed by using a T7 promoter in Escherichia coli BL21 (DE3) and the enzyme activity was detected in the cytoplasmic fraction. The optimum pH and temperature of this enzyme for levan formation was pH 6 and $30^{\circ}C$, respectively. The deduced amino acid sequence of the lscR gene showed a high sequence similarity (59-89%) with Gram-negative levansucrses, while the level of similarity with Gram-positive enzymes was less than 42%. Multiple alignments of levansucrase sequences reported from Gram-negative and Gram-positive bacteria revealed seven conserved regions. A comparison of the catalytic properties and deduced amino acid sequence of lscR with those of other bacterial levansucrases strongly suggest that Gram-negative and Gram-positive levansucrases have an overall different structure, but they have a similar structure at the active site.

• Journal of Microbiology
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• v.45 no.6
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• pp.479-484
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• 2007

Bacterial communities at 10 cm, 100 cm, and 200 cm depths in a 100-year-old lead-zinc tailing heap were evaluated by constructing 16S rRNA gene libraries. In total, 98 operational taxonomic units (OTUs) were identified from 193 clones at a 3% sequence difference level. The OTU number and species richness decreased with the depth. Species composition was significantly different between the three libraries. Fifty-seven percent of the examined clones were Acidobacteria and 27% belonged to Proteobacteria. Other sequences included Chloroflexi, Firmicutes, Chlamydiae, Actinobacteria, Gemmatimonadetes, Nitrospira, and three unclassified OTUs. Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, and Actinobacteria were mainly distributed in the rhizosphere of naturally colonizing plants; however, Deltaproteobacteria, Acidobacteria, and Chloroflexi tended to inhabit the deeper tailings (below the 100 cm-depth).

• Genomics & Informatics
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• v.4 no.4
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• pp.182-187
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• 2006

6-Phosphogluconolactonase (6PGL) is one of the key enzymes in the ubiquitous pathways of central carbon metabolism, but bacterial 6PGL had been long known as a missing enzyme even after complete bacterial genome sequence information became available. Although recent experimental characterization suggests that there are two types of 6PGLs (DevB and YbhE), their phylogenetic distribution is severely biased. Here we present that proteins in COG group previously described as 3-oarboxymuconate cyclase (COG2706) are actually the YbhE-type 6PGLs, which are widely distributed in Proteobacteria and Fimicutes. This case exemplifies how erroneous functional description of a member in the reference database commonly used in transitive genome annotation cause systematic problem in the prediction of genes even with universal cellular functions.

• Journal of Environmental Science International
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• v.28 no.10
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• pp.899-905
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• 2019

Recently, an innovative method for wastewater treatment and nutrient removal was developed by combining the sequence batch reactor and membrane bioreactor to overcome pollution caused by shipboard sewage. This system is a modified form of the activated sludge process and involves repeated cycles of mixing and aeration. In the present study, the bacterial diversity and dominant microbial community in this wastewater treatment system were studied using the MACROGEN next generation sequencing technique. A high diversity of bacteria was observed in anaerobic and aerobic bioreactors, with approximately 486 species. Microbial diversity and the presence of beneficial species are crucial for an effective biological shipboard wastewater treatment system. The Arcobacter genus was dominant in the anaerobic tank, which mainly contained Arcobacter lanthieri (8.24%), followed by Acinetobacter jahnsonii (5.81%). However, the dominant bacterial species in the aerobic bioreactor were Terrimonas lutea (7.24%) and Rubrivivax gelatinosus (4.95%).

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.215-222
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• 2023

In 2022, research for native prokaryotic species in Korea reported 10 unrecorded bacterial strains affiliated to phyla Actinomycetota, Bacillota, and Pseudomonadota. The strains formed monophyletic clades with the most closely related species (with ≥98.7% sequence similarity) in the 16S rRNA gene sequencing. Among them, four species of the phylum Actinomycetota, two species of the phylum Bacillota, and four species of the phylum Pseudomonadota have not been reported in Korea, suggesting unrecorded species in Korea. Information on strains such as Gram staining reaction, colony and cell morphology, biochemical characteristics, and isolation sources were provided in the species description.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.67-75
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• 2003

One large topic in comparative genomics is to predict functional annotation by classifying protein sequences. Computational approaches for function prediction include protein structure prediction, sequence alignment and domain prediction or binding site prediction. This paper is on another computational approach searching for sets of homologous sequences from sequence similarity graph. Methods based on similarity graph do not need previous knowledges about sequences, but largely depend on the researcher's subjective threshold settings. In this paper, we propose a genome sequence clustering method of iterative testing and graph decomposition, and a simple method to calculate a strict threshold having biochemical meaning. Proposed method was applied to known bacterial genome sequences and the result was shown with the BAG algorithm's. Result clusters are lacking some completeness, but the confidence level is very high and the method does not need user-defined thresholds.

• The Plant Pathology Journal
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• v.15 no.6
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• pp.313-318
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• 1999

Cloning of the 5'untranslated region (5' UTR) and Nterminus of the glycoprotein precursor (G2G1) open reading frame of tomato spotted wilt virus has been problematic, possibly because of the toxicity of a signal peptide at the beginning of th G2G1 protein precursor. The toxicity of the signal peptide to bacterial growth and the reason for the expression of the peptide gene in Escherichia coli were investigated by cloning the 5' UTR and the signal peptide sequence separately. Cells transformed with the plasmid containing both the first 30 amino acids of the glycoprotein and the 5' UTR showed a severe growth inhibition whereas transformants harboring either the plasmid with the signal sequence or the 5'UTR alone did not show any ingibition. An E. coli promoter-like sequence was found in the 5'UTR and tis promoter acivity was confirmed with a promoter-less GUS gene cloned downstream of the 5'UTR. In the cloning of the Tomato spotted wilt virus (TSWV) glycoprotein G2G1 open reading frame all the recovered plasmids contained stop codons in the signal sequence region. However, clones containing no stop codon were recovered when the signal sequence and the 5'UTR were cloned separately.