• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.6
• /
• pp.882-887
• /
• 2014

We studied oocyte steroidogenesis in blacktip grouper Epinephelus fasciatus ovarian follicles during vitellogenesis. Vitellogenic oocytes with average diameters of 0.45, 0.48 and 0.50 mm were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone as a precursor. The steroid metabolites were analyzed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC/MS). The major metabolites in the vitellogenic oocytes were androstenedione ($A_4$), testosterone (T), estradiol-$17{\beta}$ ($E_2$), and estrone ($E_1$). The metabolites of androgen ($A_4$ and T) were higher in the 0.50-mm oocytes than in the 0.45- and 0.48-mm oocytes, while the estrogen metabolites (E2 and E1) were lower in the 0.50-mm oocytes. These results suggest that 0.50-mm oocytes are fully vitellogenic following initiation of the maturation process.

• Applied Biological Chemistry
• /
• v.40 no.2
• /
• pp.101-106
• /
• 1997

A screening was performed to isolate the cellulose-producing microorganisms from vinegar in Korea. The isolated strain was identified as Acetobacter sp. with respect to physiological and biochemical characteristics and designated as Acetobacter CBI-2. Cellulose production of Acetobacter CBI-2 was equal with the well known cellulose-producing bacteria, A. xylinum. The result of separation on thin layer chromatography(TLC) was consistent with the degradation product of native cellulose. The presence of genes required for the cellulose biosynthesis in Acetobacter CBI-2 was confirmed by Southern hybridization.

• Korean journal of food and cookery science
• /
• v.13 no.1
• /
• pp.56-63
• /
• 1997

Antimicrobial activity of Sancho (Zanthoxylum schinifolium) was investigated. Methanol extract of dried Sancho was fractionated to hexane, chloroform, ethylacetate, butanol, and aqueous fractions. Chloroform fraction among these fractions showed the highest inhibitory effect on the microorganisms such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Lactobacillus plantarum at 1000 $\mu\textrm{g}$/$m\ell$. Chloroform fraction was further fractionated into 4 fractions by silica gel column and thin layer chromatography (TLC). The fraction 3 on TLC exhibited the highest antimicrobial activity. In the 2nd fractionation, subfration 2 was identified as hexadecanoic acid by MS, $^1$H-NMR and IR.

• Preventive Nutrition and Food Science
• /
• v.1 no.1
• /
• pp.59-63
• /
• 1996

The antimicrobial activity of mugwort(artemisia asiatica Nakai) was investigated. The methanol extract or dried mugwort was fractionated to hexane, chloroform, ethylacetate, butanol, and aqueous fractions. The hexane fraction among these fractions showed the hifhest inhibitory effect on the growth of microorganisms such as Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Lactobacillus plantarum. Bacillus subtilis, Escherchia coli, and Staphylococcus aureus were completely inhibited at a concentration of 250, 500 , and 750$\mu\textrm{g}$/ml respectively. The hexane fraction was further fractionated into 16 subfractions by silica gel column and thin layer chromatography(TLC). The subfraction No. 8, 9, and 10 on TLC exhibited high antimicrnial activity. At 3rd fractionation, subfraction No. 2 inhibited the growth of microorganisms at 500$\mu\textrm{g}$/ml. Heptadecane, dodecamethyi cyclohexasiloxane, (E,E)-2,4-decadienal, dodecamethul pentasiloxane, coumarin, 5,6,6,6a-tetrahydro-4,4,7a-trimethyl-2(4H)-benzofuranone, neophytadiene, tridecanoic acid, methyl ester, 2-methyl-4,5-nonadiene, (Z,Z)-9-12-octadecadienoyl chloride, and bis(2-ethylhexyl) were identified from this antimicrobial fraction by GC-MS.

• Journal of Life Science
• /
• v.29 no.1
• /
• pp.90-96
• /
• 2019

The objective of this study was to evaluate the potential of Diospyros malabarica stem extract, a natural materials, in oral health material. With this aim in mind, thin layer chromatography (TLC), TLC-bioautography, high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and real-time qPCR were performed. The antibacterial activity of D. malabarica stem extract against Streptococcus mutans KCTC3065 was confirmed in an n-hexane fraction with low polarity. The molecular weight of the antibacterial compound was estimated to be 188 by ESI-MS analysis. The inhibitory effects of the extract on biofilm formation and gene expression related to biofilm formation of S. mutans were determined by SEM and real-time PCR analysis. The extract inhibited the formation of S. mutans biofilms at D. malabarica stem extract concentrations of 1 mg/ml, as shown by SEM. The real-time PCR analysis showed that the expression of the gtfC gene, which is associated with biofilm formation, was significantly decreased in a dose-dependent manner. Based on the above results, it can be concluded that D. malabarica stem extracts, a natural materials, can be used in oral health products to suppress the formation of biofilms by inhibiting tooth adhesion of S. mutans, a causative agent of dental caries.

• Journal of Life Science
• /
• v.16 no.6
• /
• pp.989-993
• /
• 2006

The antimicrobial substance from Pyrola japonica were extracted and isolated. Eighty percent ethanol extract of dried Pyrola japonica was fractionated to hexane, diethyl ether, ethyl acetate and aqueous layer. The hexane-soluble fraction showed the highest inhibitory activity against Bacillus subtilis. Moreover the hexane layer was fractionated into 5 groups by silica gel column chromatography. From the results, group No. 2 ($18{\sim}40$ fractions) showed the highest antimicrobial activity. The group was re-separated to 10 fractions by preparative thin layer chromatography and the peak I as active fraction was isolated by HPLC.

• Food Engineering Progress
• /
• v.14 no.2
• /
• pp.159-165
• /
• 2010

Red ginseng tail roots (9.8 g water/100 g sample) were puffed at 7, 8, 9, and 10 $kg_{f}/cm^{2}$ using a rotational puffing gun. Puffed red ginseng was extracted with 70% ethanol, and the concentrated extract was successively partitioned with diethyl ether, n-butanol and $H_{2}O$. Two unknown ginsenosides from puffed red ginseng were found at 63 and 65 min of retention time in HPLC chromatogram suggesting that chemical structure of some ginsenosides might be altered during the puffing process. Identification of two unknown compounds was carried out using TLC, HPLC and NMR. Two major compounds were isolated from TLC. According to TLC result, compound I was expected to be the mixture of ginsenosides Rk1 and Rg5, and compound II was expected to be a 20(S)-ginsenoside $Rg_{3}$. Three compounds were isolated from n-butanol fraction through repeated silica gel and octadecyl silica gel column chromatographies. From the result of $^{1}H$- and $^{13}C$-NMR data, the chemical structures of unknown compounds were determined as ginsenoside $Rg_{5}$ and 20(S)-ginsenoside $Rg_{3}$. Unfortunately, ginsenoside $Rk_{1}$ could not be separated from ginsenoside-$Rg_{5}$ in the compound I. It was carefully reexamined using HPLC and confirmed that the last unknown compound was ginsenoside-$Rk_{1}$.

• Microbiology and Biotechnology Letters
• /
• v.52 no.2
• /
• pp.135-140
• /
• 2024

This study reports the isolation of a bacterium capable of degrading agar and the characterization of its agarase. An agar-degrading marine bacterium JS-1 was isolated using Marine agar 2216 media from seawater collected from the seashore of Angolpo, Changwon, Gyeongnam Province, Republic of Korea. An agar-degrading bacterium was named as Tenacibaculum sp. JS-1 by phylogenetic analysis based on 16S rRNA gene sequence. The extracellular crude agarase was prepared from the culture media of Tenacibaculum sp. JS-1 and used for characterization. Relative activities at 20, 30, 40, 50, and 60℃ were 39, 73, 100, 74, and 53%, respectively. Relative activities at pH 5, 6, 7, and 8 were 46%, 67%, 100%, and 49%, respectively. Its extracellular agarase showed maximum activity (164 U/l) at pH 7.0 and 40℃ in a 20 mM GTA buffer. The residual activities after heat treatment at 20, 30, and 50℃ for 30 min were 84, 73, and 26% or more, respectively. After 2 h heat treatment at 20, 30, 40, and 50℃, the residual activities were 80, 64, 52 and 21%, respectively. Thin layer chromatography analysis suggested that Tenacibaculum sp. JS-1 produces extracellular β-agarases that hydrolyze agarose to produce neoagarooligosaccharides, including neoagarohexaose (12.3%), neoagarotetraose (65.1%), and neoagarobiose (22.6%) at 6 h. Tenacibaculum sp. JS-1 and its β-agarase could be valuable for producing neoagarooligosaccharides with a variety of functional properties. These properties include inhibiting bacterial growth, slowing down starch degradation, and whitening, which are of interest for pharmaceuticals, food, cosmeceuticals, and nutraceuticals.

• Applied Chemistry for Engineering
• /
• v.4 no.3
• /
• pp.505-514
• /
• 1993

Defined oligoglycerol monolaurate esters were synthesized by means of step by step synthesis methods, and monoglycerol monolaurate, diglycerol monolaurate, symmetrical triglycerol monolaurate and symmetrical tetraglycerol monolaurate were obtained in a rate of 85~95% yields. All the reacted products could be separated by means of column and thin layer chromatography, and the structure of products has been analyzed with IR, $^1H\;NMR$ spectra respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.11 no.3
• /
• pp.35-36
• /
• 1982

Lipid composition of human milk samples (ten colostrum and 10 mature) was analyzed by quantitative thin-layer chromatography with flame ionization detector. Six kinds of lipid components existed in human milk. Among them, triglyceride which was most abundant lipid component showed significantly lower levels in colostrum than in mature milk. Other lipid components have no significant differences between colostrum and mature milk.