• Animal Systematics, Evolution and Diversity
• /
• v.34 no.4
• /
• pp.208-214
• /
• 2018

The genus Luidia belongs to the family Luidiidae in the order Paxillosida. It is a common littoral taxon, and the depth range of the Korean fauna is generally 0-100 m. However, specimens of Luidia were collected from Jeju Island in Korea at 150-160 m depth and identified as Luidia sagamina sagamina $D{\ddot{o}}derlein$, 1920. This species is determined by morphological characteristics and mitochondrial cytochrome c oxidase subunit I sequence analysis. Luidia sagamina sagamina is a very rare sea star in worldwide and it only collected previously from Sagami Bay, Japan, and is newly reported in Korea. Four species of Luidia, including L. s. sagamina, are recorded in the Korean fauna.

• Animal Systematics, Evolution and Diversity
• /
• v.34 no.4
• /
• pp.215-219
• /
• 2018

Protochitonidae Ashby, 1925 is a family of small to medium sized chitons that includes a single fossil genus and two extant genera. Of the two extant genera, Deshayesiella Carpenter in Dall, 1879 contains 5 described species. Although most Deshayesiella species are known to be found in deep sea habitats(over 100 m), D. curvata (Carpenter in Pilsbry, 1892) is found from shallow waters(1-20 m). In this study, we provide details of microstructure of shell and radula characters using scanning electron microscopy and morphological features of D. curvata, and its partial sequence of mitochondrial DNA cox1 gene as DNA barcode sequence. In addition, we compare morphological differences of D. curvata from other congeneric species.

• Journal of the Korea Safety Management & Science
• /
• v.19 no.4
• /
• pp.253-260
• /
• 2017

Due to dramatic changes in the trend of corporate management in economics, labor and government, companies are being asked to adapt creative and innovative organizational culture in order to keep sustainability. Under the circumstances, flexible working hour becomes one of very effective method for organization culture improvement. Recently, M company has introduced the new policy of working hours that employees can choose a couple of different time options depending on their personal situations. And it turns out to be very effective to work & life balance, increasing organizational vitality, improving efficiency of business and productivity, recruitment of core human resources, and prevention of deviation; both team and personal performance levels has significantly improved. Therefore, it is highly recommended to adapt flexible working policies for companies seeking for a long term, sustainable corporate vision.

• Korean Journal of Environmental Biology
• /
• v.39 no.3
• /
• pp.399-405
• /
• 2021

Until now, five species (Meghimatium bilineatum, M. fruhstorferi, Limax flavus, L. marginatus, Deroceras reticulatum) in three genera of families Philomycidae and Limacidae have been reported in Korea. Philomycidae is a family of air-breathing land snails. Meghimatium hongdoensis sp. nov. is described based on its middle size (60-80 mm in body length), its body coloration (dark-red yellow), no dorsal with streaks, its genitalia, and 16rDNA sequence analysis. Specimens of this new species were collected from Hongdo island, Sinan-gun, Jeollanam-do, Korea. This species is only known from the type locality at Hongdo to date. It could be found in high-humidity sites. Meghimatium uniforme (Laidlaw 1937) was the first one reported in Korea. It was also collected from Gageodo island, Sinan-gun, Jeollanam-do, Korea. In this study, morphological characteristics including their radula and genital structures of these two species were described. Preliminary results of mitochondrial 16S rDNA sequencing and phylogenetic analyses indicated that these species belonged to the Korean clade.

• Bulletin of the Korean Mathematical Society
• /
• v.56 no.5
• /
• pp.1219-1233
• /
• 2019

Let $E{\rightarrow}M$ be an arbitrary vector bundle of rank k over a Riemannian manifold M equipped with a fiber metric and a compatible connection $D^E$. R. Albuquerque constructed a general class of (two-weights) spherically symmetric metrics on E. In this paper, we give a characterization of locally symmetric spherically symmetric metrics on E in the case when $D^E$ is flat. We study also the Einstein property on E proving, among other results, that if $k{\geq}2$ and the base manifold is Einstein with positive constant scalar curvature, then there is a 1-parameter family of Einstein spherically symmetric metrics on E, which are not Ricci-flat.

• BMB Reports
• /
• v.53 no.12
• /
• pp.611-621
• /
• 2020

Bacterial endoribonuclease toxins belong to a protein family that inhibits bacterial growth by degrading mRNA or rRNA sequences. The toxin genes are organized in pairs with its cognate antitoxins in the chromosome and thus the activities of the toxins are antagonized by antitoxin proteins or RNAs during active translation. In response to a variety of cellular stresses, the endoribonuclease toxins appear to be released from antitoxin molecules via proteolytic cleavage of antitoxin proteins or preferential degradation of antitoxin RNAs and cleave a diverse range of mRNA or rRNA sequences in a sequence-specific or codon-specific manner, resulting in various biological phenomena such as antibiotic tolerance and persister cell formation. Given that substrate specificity of each endoribonuclease toxin is determined by its structure and the composition of active site residues, we summarize the biology, structure, and substrate specificity of the updated bacterial endoribonuclease toxins.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.217.3-217.3
• /
• 2003

Acetyl-L-carnitine, a physiological component of the L-carnitine family, has been proposed for treating Alzheimer's disease in pharmacological doses. Acetyl-L-carnitine and d3-acetylcarnitine (internal standard) were analyzed by electrospray ionization / tandem mass spectrometry (ESI/MS/MS) after derivatization to their butylesters through treatment with butanolic hydrogen chloride. Acetyl-L-carnitine produced a protonated precursor ion at m/z 260 and a corresponding product ion of m/z 85. Analytes were separated on a Capcell Pak C18 (2.0${\times}$150mm, 5 mm). (omitted)

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.336.1-336.1
• /
• 2002

HSP100/Clp family functions as molecular chaperone and ATP dependent protease. The Streptococcus pneumoniae ClpL. a homologue of bacterial ClpB and yeast cytosolic HSP 104. is one of major heat shock proteins but its biochemical properties are unknown. In this study. ClpL in Streptococcus pneumoniaewas characterized using histidine tagged recombinant ClpL. When ATP hydrolysis activity was compared in the presence or absence of a variety of nucleotides or divalent ions. either ATP or Mn$2^＋$ ion was found to increase significantly the rate of ATP hydrolysis. Furthermore. glutaraldehyde cross-linking and subsequent native-PAGE analfysis showed that ClpL forms dimer. but in the presence of 4 mM concentration of $Mn^{2＋}$ion as a cofactor for ATP hydrolysis and oligormerization in vitro.

• Korean Journal of Food Science and Technology
• /
• v.53 no.3
• /
• pp.348-355
• /
• 2021

Bacteriophages (phages) are known determinants of kimchi microbial ecology. Lactobacillus plantarum is related to kimchi over-acidification during the late stages of kimchi fermentation. A phage infecting Lac. plantarum was isolated from kimchi and characterized. The phage population for kimchi in a market was 2.3 log particles/mL, which corresponded to 32% of the bacterial population on a log scale. The isolated phage was designated as ΦLP12116. ΦLP12116 which belonged to the Siphoviridae family and has a very narrow host range, infecting only Lac. plantarum. The phage was stable at a lactic acid concentration of 1.0% and pH 4.0 at 4℃, indicating that it could survive in kimchi. In the kimchi extract broth treated by the phage, the growth of Lac. plantarum KCCM 12116 was inhibited by 2.2 log CFU/mL compared to the growth in non-phage-treated broth. Therefore, this study suggests that the growth of Lac. plantarum, which is known as an acid-producing strain during late fermentation in kimchi, may be controlled using the phage.

• Journal of Species Research
• /
• v.11 no.4
• /
• pp.330-334
• /
• 2022

Mesorhabditis microbursaris (Steiner, 1926) Sudhaus, 2011, belonging to the family Mesorhabditidae (Rhabditomorpha), is newly reported from South Korea. During a survey of small streams, M. microbursaris was isolated from sedimentary soil samples. The genus Mesorhabditis Osche, 1952 nematodes are distributed all over the world and are mostly found from terrestrial habitats, however are sometimes found in freshwater. At present, 34 valid species have been recorded from Mesorhabditis; however, only three species have been reported from South Korea. Mesorhabditis microbursaris exhibits morphological characters of other congeneric species, including shorter distance between vulva and anus than the distance between anus and tail, rudimentary bursa with narrow velum and short genital papillae, shorter spicules than tail and conical tail. However, this species can be distinguished from other Mesorhabditis species by its morphometric characters and three pairs of bursal papillae. Details of the morphological characteristics and morphometrics of M. microbursaris are described and illustrated based on optical microscopy.