• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.3
• /
• pp.445-450
• /
• 2002

This study was performed to evaluate the effect of chitosan addition on shelf life of bread. Four different molecular weights (MW) of chitosan, 1 kDa, 5 kDa, 30 kDa, and 120 kDa were used. The growth of spoilage bacteria was inhibited depending on MW and concentration of chitosan, and most inhibited conditions were 0.1% of 30 kDa and 120 kDa of chitosans. But the growth of yeast and mold showed very weak inhibition. This showed that yeast would grow normaly in the fermentation process of bread. Shelf-life of bread was improved depending on concentration of chitosans at WM 30 kDa and 120 kDa. Antioxidative effect of chitosan was increased with the larger molecular weight and the higher concentration during storage. The preservation of bread by adding chitosan was improved.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.9
• /
• pp.637-643
• /
• 2012

This study was carried out to investigate how reversible and irreversible fouling were distributed in the filtration using ceramic membrane of 300 kDa pore size for secondary effluent of wastewater. It was performed by calculating fouling as numerical method for diverse TMPs and measured F-EEM and SEC for raw water, treated water and backwashed water. Water quality was also checked to know whether treated water quality was stable or not. The results showed that reversible fouling formation was increased when lower TMP was applied and it is caused by protein like organic matters having higher molecular weights. The secondary wastewater effluent had diverse molecular weight materials, especially contaminants lower than 0.5 kDa and bigger than 12 kDa. Decreasing TMP induced contaminants above 12 kDa and below 1 kDa to become reversible fouling.

• The Korean Journal of Mycology
• /
• v.23 no.4 s.75
• /
• pp.340-347
• /
• 1995

Polysaccharide FHW was extracted from the fruiting bodies of Fomitella fraxinea with hot-water treatment and then fractionated into FHW-I and FHW-II on DEAE-Cellulose chromatography. FHW-I and FCW-II were further purified into FHW-Ia and Ib, FHW-IIa and IIb on gel permeation chromatography, respectively. A small amount of uronic acid was detected and glucose, galactose, fucose, and mannose were found to be main sugars in the polysaccharides. Protein was detected in FHW-Ia, FHW-IIa, and FHW-IIb, but not in FHW-Ib. FHW-Ia was identified to be a fuco-gluco-mannogalactan with molecular weight of 19,000 and FHW-Ib was a gluco-fuco-mannogalactan of 15,000. FHW-IIa and FHW-IIb were galacto-mannoglucan and their molecular weights were estimated to be 31,000 and 9,000, respectively. Both FHW-Ib and FHW-IIb did not show an absorption band characteristic of the ${\beta}-glycosidic$ linkage in IR spectra. FHW-IIb showed a strong immuno-stimulating activity but the other three polysaccharides showed a weak activity.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.5
• /
• pp.455-460
• /
• 1991

In order to identify hard distinct 12 fish species(shiba shrimp Metapenaeus joyneri, fleshy shrimp Penaeus orientalis, ridgetail prawn Palaemon carinicauda, yellow croaker Pseudosciaena manchurica, croaker Niber albiflora, Colichthyes fragilis, brown sole Limanda herzensteini, frog flounder Pleuronichthys cornutrs, Areliscus rhomaleus, stone flounder Kareius bicoloratus, harvest fish Pampus argenteus, flag fish Goniistius zonatus) by seeing with naked eye in Kunsan coastal area, sarcoplasmic protein in the supernatant was used for isoelectric focusing. For getting supernatant, fish muscle tissue was blended with two times deionized water and centrifuged (at $4^{\circ}C$, 12,000rpm for 15min). Isoelectric focusing of sarcoploasmic protein carried out on a LKB Multiphor II using polyacrylamide gel plate (2mm thickness, pH $3.5~10^{\circ}C$, pH 5~8 gradient, at $10^{\circ}C$ for 1.5, 3 hours). In case of uncertain protein pattern, pH gradient was modified to narrow pH gradiet, and excuted 2-D electrophoresis using conventional polyacrylamide gel electrophoresis. Most of fishes except yellow croaker and Collichthyes fragilis were distingushed by isoelectric focusing. The protein maps of 2-D electrophoresis for analyzing two protein bands at aimilar positions(pH 5, 6) between the two fish species showed the diffeences of the estimated molecular weights, 11,700(pH5.0) and 87,000(pH6.0)

• Journal of Applied Biological Chemistry
• /
• v.63 no.4
• /
• pp.387-392
• /
• 2020

Pseudomonas tolaasii is a pathogen causing brown blotch disease in cultivated mushrooms. In previous study, various strains of P. tolaasii were isolated from the mushrooms with disease symptoms and they were further divided into Ptα, Ptβ, and Ptγ subtypes according to the 16S rRNA gene analysis. To investigate the secretion of peptide toxins, tolaasin and its analog peptides, culture extracts of Pt group strains were analyzed by gel permeation chromatography. Those of Ptα subtype strains contained two chromatographic peaks, band A and B. Meanwhile, those of Ptβ and Ptγ subtype strains contained mainly band A component and a little of band B. Molecular weights of toxic peptides of culture extracts were measured by MALDI-TOF mass spectrometry. In Ptα subtype strains, the peptide compositions of band A and B were same including tolaasin I (1,987 Da), tolaasin II (1,943 Da), and its two analog peptides, 1,973 Da and 2,005 Da. The strains of Ptβ and Ptγ subtype secreted many components of MW 1,100-1,200 Da, but they did not synthesize any tolaasin-like peptides. These results suggest that the only Ptα subtype strains secrete tolaasin and its analog peptide toxins and the strains of Ptβ and Ptγ subtypes have different pathogenic characters causing brown blotch disease.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.4
• /
• pp.58-65
• /
• 2004

This study was performed to investigate the protease activity from fruit body of Sarcodon aspratus and its features. The specific protease activity was increased with the increasing purification steps, 2.62 times by desalting, 17 times by CMC column chromatography, 113.8 times by DEAE-Sephadex A-50 column chromatography, and 728.3 times by Sephadex G-75 column chromatography. Proteases were identified as two different enzymes having different isoelectric points at pH 4.35 (its recovery rate 8%) and pH 4.7 (its recovery rate 3.5%). Those proteases were purified by 3,025 folds and 3,257 folds in terms of specific activity. Two proteases having different isoelectric points had similar enzymatic properties. This protease was estimated to be 43,000 daltons of molecular weights by SDS-PAGE. This protease with optimum pH 4 was almost stable in the pH range of 4~7. Optimal temperature of protease activity was 40 to 50℃, and the protease activity was completely inhibited at 70℃ for 30 min.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.5
• /
• pp.12-19
• /
• 2004

This study was performed to investigate the optimum condition of protease production from submerged culture of oak mushroom (Lentinula edodes, Sanlim No. 5) and its enzymatic features. Among several combinations of media, the combination of wheat bran, corn flour, water and corn oil (WB+CF+W+ CO) yielded 84.8 U/g of maximum protease activity. This combination of ingredients, in spite of not being particularly protein-rich in comparison to the other media, allowed for good growth of the fungus and maximal protease production. Comparison of different growth medium liquids indicated that demineralized water afforded the best growth of the fungus and the highest protease activity. Acetate buffer and acidified water negatively affected The protease production peaked around 72 hr of incubation, and decreased thereafter. The molecular weights of produced protease were about 45,000 by Sephadex G-75 chromatography. The pH optimum for protease activity was 4, while maximal activity incubated at 37℃ for 1 hr was observed between pH 4~6. The optimum temperature of this protease was 55℃, and the enzyme was active over a broad temperature range (30~60℃), indicating that this protease would be suitable for a wide range of applications where. different pH and temperature are necessary, such as digestive aids, food industry, beer and tannery industries.

• Korean journal of applied entomology
• /
• v.24 no.1 s.62
• /
• pp.45-50
• /
• 1985

The use of a modified procedure for the isolation of extrachromosomal DNA of low to high molecular weight, followed by agarose gel electrophoresis of the crude lysates, provided a simple screening procedure for detecting plasmids ranging in molecular weights from approximately 1 to more than 135 megadaltons from serovars of Bacillus thuringiensis. The procedure provides for a relatively large-volume stable lysate for isolation of plasmids for restriction endonuclease mapping and cloning procedures. The method was used for screening of plasm ids in 6 differenentially effective serovars of B. thuringiensis toxic to dipteran and lepidopteran insects. Relatively large plasmid DNAs of masses above 50 megadaltons (Mdal) were isolated from all of the serovars examined using this technique. The number of extrachromosomal DNAs detected in serovars of B. thuringiensis was 8 for israelensis, 10 for kurstaki, 13 for aizawai, 2 for dendrolimus, 1 for finitimus, and 6 for yunnanensis. Smaller plasmid DNAs were isolated in four of the six serovars that ranged in mass down to approximately 2 Mdal.

• Applied Biological Chemistry
• /
• v.23 no.1
• /
• pp.23-30
• /
• 1980

Labelling of chromatin proteins with 32P was observed after incubating isolated liver nuclei with $[{\gamma}-32P]$ ATP for 5 minutes at $37^{\circ}C$. The pattern of labelling with 32P was examined on SDS polyacrylamide gel electrophoresis with nuclei from rats maintained in a starvation state for 48 hours, following refeeding for 12 hours; and from fed streptozotocin-diabetic rats with insulin injection 6 hours before sacrifice. With 48h starved rat liver nuclei the level of phosphorylation for 0.14M NaCl soluble proteins was decreased in the molecular weights between 41,000 and 200,000 daltons relative to normal controls. Refeeding the starved rats reversed the change of phosphorylation pattern over 12 hour The level of phosphorylation for five phenol soluble non-histone proteins with molecular weights above 59,000 daltons was somewhat decreased with 48h starved rat liver nuclei as compared with that of normal controls. Starvation also decreased the phosphorylation level of major histones in relation to normal controls. The experiment with insulin injection into fed streptozotocin-diabetic rats showed the tendency to increase phosphorylation of 0.14M NaCl soluble proteins (130,000 dalton protein) and phenol soluble non-histone proteins (155,000 dalton protein). The phosphorylation level of histones appeared to be invariant under the experimental conditoins employed here. These results suggest the possibility that the phosphorylation and dephosphorylation of 0.14M NaCl soluble proteins and $H_1$ histone precede those of other chromatin associated nuclear proteins, It is of interest to find that insulin signal was correlated to phosphorylation of nuclear proteins while glucagon signet dephosphorylated nuclear proteins.

• Journal of the Korean Wood Science and Technology
• /
• v.38 no.3
• /
• pp.223-229
• /
• 2010

In this study diverse dehydrogenative polymers (DHPs) were synthesized with three precursors of native lignin [p-coumaryl alcohol (PCA), coniferyl alcohol (CA), sinapyl alcohol (SA)] in the presence of horseradish peroxidase (HRP, EC. 1.11.1.7)/$H_2O_2$. To compare the structural features between DHPs and native lignin, the DHPs as well as pine/poplar milled wood lignins were simultaneously subjected to gel permeation chromatography (GPC) to determine average molecular weights and derivatization followed by reductive cleavage (DFRC) to investigate the frequency of ${\beta}$-O-4 linkage. The highest yield of DHP was measured to 71% when CA was solely injected (G-DHP) and the yield of H-DHP was 42%. However, single injection of SA could not form any polymer in this system. The average molecular weights of DHPs were ranged between 3,000~4,700, which were only 1/2 fold compared with that of pine MWL (G-type lignin: Mw 7,340) and 1/3 scale compared with that of poplar MWL (GS-type lignin: Mw 13,250). DFRC analysis revealed that the formation of ${\beta}$-O-4 linkage during dehydrogenative polymerization was the highest in the GS-DHP with ca. 502 ${\mu}mol$/g, which was, however, remained to only 50% compared to that in poplar MWL (1107 ${\mu}mol$/g). The ${\beta}$-O-4 linkage was estimated to ca. 286 ${\mu}mol$/g In the G-DHP, which was twice as much as that of H-DHP(127 ${\mu}mol$/g). Similar to GS-DHP, only half amount of ${\beta}$-O-4 linkage, compared to pine MWL, was formed during in vitro polymerization of CA by horseradish peroxidase/$H_2O_2$.