Sungkyunkwan University · Biochemistry, Genetics and Molecular Biology
Professor Jung-Hoon Yoon's research lab specializes in microbial ecology and biotechnology, with a focus on isolating and characterizing novel halophilic and extremophilic microorganisms from marine and coastal environments such as salt marshes and tidal flats. The lab investigates the taxonomic, physiological, and biochemical properties of these microbes, particularly those with potential applications in bioremediation, industrial enzymes, and biotechnology. Additionally, the lab explores the molecular mechanisms of carcinogenesis, especially the role of environmental mutagens and epigenetic changes like CpG methylation in tumor suppressor genes such as RASSF1A and p53 in human cancers.
Figures are computed from collected data and may differ slightly.
Two Gram-negative, non-motile, non-spore-forming and moderately halophilic cocci (strains YKJ-103T and YKJ-105) were isolated from the traditional Korean fermented seafood, jeotgal. The two strains grew optimally at 25-30 degrees C and grew at 4 and 36 degrees C, but not above 37 degrees C. They grew in the presence of 0-10% (w/v) NaCl with an optimum of 2-3% (w/v) NaCl. Strains YKJ-103T and YKJ-105 were chemotaxonomically characterized by having ubiquinone-8 (0-8) as the predominant isoprenoid
A Gram-negative, non-motile, non-spore-forming, moderately halophilic rod (strain SM-1T) was isolated from salt marsh around the junction of the Youngsan River and the Yellow Sea in Korea and subjected to a polyphasic taxonomic study. This organism grew optimally at 37 degrees C and was able to grow at 10 and 45 degrees C. It grew optimally in the presence of 2-3% (w/v) NaCl. The major fatty acids in strain SM-1T were iso-C15:0 and C16:0. Strain SM-1T and Microbulbifer hydrolyticus DSM 11525T we
A large fraction of the p53 mutations in lung cancers from smokers are G-to-T transversions, a type of mutation that is infrequent in lung cancers from nonsmokers and in most other tumors. Previous studies have indicated that there is an association between G-to-T transversion hotspots in lung cancers and sites of preferential formation of polycyclic aromatic hydrocarbon adducts along the p53 gene. p53 codons containing methylated CpG sequences are preferential targets for formation of adducts b
Homozygous deletion and loss of heterozygosity (LOH) at chromosome 3p21 have been observed in several types of human cancer including lung cancer and breast cancer. In previous work, we cloned and identified the human RAS association domain family 1A gene (RASSF1A) from the lung tumor suppressor locus 3p21.3. The CpG island and promoter region of RASSF1A is highly methylated in primary lung and breast tumors. In this study, we analyzed the methylation status of the promoter region of RASSF1A in
Two Gram-positive or Gram-variable, endospore-forming, moderately halophilic rods (strains TF-11(T) and TF-12(T)) were isolated from a tidal flat of the Yellow Sea in Korea and were subjected to a polyphasic taxonomic study. Strains TF-11(T) and TF-12(T) had cell-wall peptidoglycan based on meso-diaminopimelic acid. The predominant menaquinone found in the two strains was MK-7. The cellular fatty acid profiles of both strains contained large amounts of branched and saturated fatty acids. The maj
A new lipase, LipEH166, isolated from an intertidal flat metagenome, showed no amino acid similarity to any known lipolytic enzyme except in the consensus region. This suggested that LipEH166 and its homologues belong to a new family of lipolytic enzymes. Partial characterization indicated that LipEH166 is a novel cold-adapted alkaline lipase.
The repair enzymes thymine DNA glycosylase (TDG) and methyl-CpG-binding protein 4 (MBD4) remove thymines from T:G mismatches resulting from deamination of 5-methylcytosine. Thymine glycol, a common DNA lesion produced by oxidative stress, can arise from oxidation of thymine or from oxidative deamination of 5-methylcytosine, and is then present opposite adenine or opposite guanine, respectively. Here we have used oligonucleotides with thymine glycol incorporated into different sequence contexts a
Two gram-negative, motile, non-spore-forming, yellow-pigmented and slightly halophilic strains (SW-46T and SW-52) were isolated from sea water of the East Sea, Korea, and subjected to a polyphasic taxonomic study. Strains SW-46T and SW-52 were characterized chemotaxonomically by having ubiquinone-10 (Q-10) as the predominant respiratory lipoquinone and C18:1 omega7c as the major fatty acid. Their DNA G + C content was 64.0-64.1 mol%. Strains SW-46T and SW-52 showed 1 bp difference in their 16S r
A Gram-variable, aerobic, endospore-forming, rod-shaped bacterial strain, SF-20(T), which was isolated from a salt field in Korea, was subjected to a polyphasic taxonomic study. Cells of this organism were motile by means of single flagella. Strain SF-20(T) grew optimally in the presence of 4-8% NaCl. The cell wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinone is MK-7. Strain SF-20(T) has a cellular fatty acid profile containing majo
Phylogenetic analysis based on 16S rRNA gene sequences revealed that Thermoactinomyces species with validly published names can be assigned to four clusters or lineages. The type strains of Thermoactinomyces sacchari and Thermoactinomyces putidus were differentiated from the type strains of Thermoactinomyces vulgaris and Thermoactinomyces intermedius by the predominant menaquinone and fatty acid profiles. The type strains of Thermoactinomyces dichotomicus and Thermoactinomyces peptonophilus form
Two Gram-positive, non-motile, non-spore-forming, halotolerant and moderately halophilic cocci (strains YKJ-101T and YKJ-115T) were isolated from the traditional Korean fermented seafood jeotgal, and were investigated using a polyphasic taxonomic approach. Phylogenetic analysis of 16S rDNA sequences showed that strains YKJ-101T and YKJ-115T are most closely related to the cluster comprising two Salinicoccus species. The peptidoglycan type of the strains is A3alpha, based on L-Lys-Gly(3-4)-L-Ala(
A Gram-variable, endospore-forming moderately halophilic rod, strain SF-121, was isolated from a marine solar saltern of the Yellow Sea in Korea. The result of 16S rRNA gene sequence analysis showed that strain SF-121 has highest sequence similarity (99.7 %) with the type strain of Bacillus halodenitrificans. Phylogenetic analyses based on 16S rRNA gene sequences revealed that B. halodenitrificans DSM 10037(T) and strain SF-121 are more closely related to the genus Virgibacillus than to the genu
A bacterial strain which is able to degrade pyridine was previously isolated from the oxic zone of an oil shale column and described as Pimelobacter sp. strain OS4T. However, Pimelobacter species have been transferred to the genera Nocardioides and Terrabacter. Strain OS4T was identified as a member of the genus Nocardioides on the basis of chemotaxonomic analysis and phylogenetic inference based on 16S ribosomal DNA (rDNA) sequence analysis. The G+C content of strain OS4T is 72.5 mol%. The cell
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