• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.608-616
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• 1996

To propose the use of skipjack processing by-product(SPB) as a food material, the optimal condition for the production of the SPB hydrolysate through enzyme treatment was obtained using RSM(Response Surface Methodology). Among eight pretenses test, Pretense $P^{TM}$ was screened primarily on the aspect of production cost and taste of the product. The extent of autolysis accompanied by endogenous enzyme in the SPB was almost negligible as compared with that of Protense $P^{TM}$ treatment. The derived model equation was within the satisfiable range as indicated by coefficient of $determination(R^2=0.9460)$ and lack of fit(p>0.1) values. From the results of RSM and ridge analysis, the conditions favoring the higllest degree of hydrolysis were: PH 7.2, $51^{\circ}C,$ reaction time of 3.94 hr, substrate concentration of 33.3%, and enzym $e_strate ratio of 0.48%.48%.8%.

• BMB Reports
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• v.28 no.5
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• pp.398-401
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• 1995

Two fibrinolytic enzymes from the autolysate of Lumbricus rubellus were purified in homogeneous form. Their molecular sizes were 31,000 (Enz1) and 35,000 (Enz2) Da. respectively. However, the N-Terminal amino acid sequences of Enz1 and Enz2 were exactly the same: Ile-Val-Gly-Gly-Ile-Glu-Ala-Arg-Pro-Tyr-Glu-Phe-Pro-Trp-Gln-. These results indicate that Enz1 is a shortened form of Enz2 formed during autolysis. When a synthetic substrate, Ile-Pro-Arg-pNA, was used, the catalytic activity were observed in the pH range of 5-10 and the kinetic parameters including $K_m$ (1.6 ${\mu}m$) and $V_{max}$ (40 nmol/jmin/mg) were almost identical between the two enzymes. However, the fibrinolytic activity of Enz2 was at least 1.25 times higher than that of Enz1, suggesting that the C-terminal region of Enz2 is important in fibrinolysis but not in amidolysis. Furtheimore. fibrinolytic activity of the enzymes was increased by the addition of the lipid extracted from L. rubellus in the presence of $MgCl_2$ or $CaCl_2$. The stimulatary effect of lipid on Enz2 was higher compared to Enz1.

• Korean Journal of Food Science and Technology
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• v.20 no.5
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• pp.650-658
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• 1988

The mobilization of proteins in the cotyledons of germinating soybean seeds (Glycine mar [L.] Merr.) and seedlings was studied by using light microscopy and transmission electron microscopy. The cotyledon tissues of soybean. were packed with protein bodies(diameter $0.1-15{\mu}m$) where storage protein of soybean is deposited. Degradation of protein bodies started in the epidermis and vascular tissues. After swelling of the protein bodies, autolysis of storage proteins began while the external membrane remained unbroken. Hydrolysis of proteins could be internal or peripheral and fusion might begin before complete protein degradation. Possible instances of vacuolar fusion were encountered in some cells. In all cases, the result of degradation was the same; the central vacuole of the cell. At the late stages of seedling growth, breakdown of tonoplast was observed in some cells.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1635-1643
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• 2009

The aim of this study was to provide new insight into the mechanism whereby the housekeeping enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) locates to cell walls of Lactobacillus plantarum 299v. After purification, cytosolic and cell wall GAPDH (cw-GAPDH) forms were characterized and shown to be identical homotetrameric active enzymes. GAPDH concentration on cell walls was growth-time dependent. Free GAPDH was not observed on the culture supernatant at any time during growth, and provoked cell lysis was not concomitant with any reassociation of GAPDH onto the cell surface. Hence, with the possibility of cw-GAPDH resulting from autolysis being unlikely, entrapment of intracellular GAPDH on the cell wall after a passive efflux through altered plasma membrane was investigated. Flow cytometry was used to assess L. plantarum 299v membrane permeabilization after labeling with propidium iodide (PI). By combining PI uptake and cw-GAPDH activity measurements, we demonstrate here that the increase in cw-GAPDH concentration from the early exponential phase to the late stationary phase is closely related to an increase in plasma membrane permeability during growth. Moreover, we observed that increases in both plasma membrane permeability and cw-GAPDH activity were delayed when glucose was added during L. plantarum 299v growth. Using a double labeling of L. plantarum 299v cells with anti-GAPDH antibodies and propidium iodide, we established unambiguously that cells with impaired membrane manifest five times more cw-GAPDH than unaltered cells. Our results show that plasma membrane permeability appears to be closely related to the efflux of GAPDH on the bacterial cell surface, offering new insight into the understanding of the cell wall location of this enzyme.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.360-369
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• 2015

Milk proteins have many potential sequences within their primary structure, each with a specific biological activity. In this study, we compared and investigated the bioactivities of hydrolysates of the domestic (A, B) and imported (C, D) skim milk powders generated using papain digestion. MALDI-TOF analysis revealed that all milk powder proteins were intact, indicating no autolysis. Electrophoretic analysis of hydrolysates showed papain treatment caused degradation of milk proteins into peptides of various size. The antioxidant activity of the hydrolysates, determined using 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and total phenolic contents (TPC) assays, increased with incubation times. In all skim milk powders, the antioxidant activities of hydrolysates were highest following 24 h papain treatment (TPC: A, 196.48 μM GE/L; B, 194.52 μM GE/L; C, 194.76 μM GE/L; D, 163.75 μM GE/L; ABTS: A, 75%; B, 72%; C, 72%; D, 57%). The number of peptide derived from skim milk powders, as determined by LC-MS/MS, was 308 for A, 283 for B, 208 for C, and 135 for D. Hydrolysate A had the highest antioxidant activity and the most potential antioxidant peptides amongst the four skim milk powder hydrolysates. A total of 4 β-lactoglobulin, 4 α_s1-casein, and 56 β-casein peptide fragments were identified as potential antioxidant peptides in hydrolysate A by LC-MS/MS. These results suggest that domestic skim milk could have applications in various industries, i.e., in the development of functional foods.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.78-82
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• 1993

This study was carried out to develop a new processing method for the production of yeast autolyzate (YA) by which the yield and the quality could be improved, compared to the conventional method. The result indicated that 85.3% of yeast cell walls treated with glucanase and protease was ruptured by homogenizing at 10,000 psi. Alkali treatment, however, was not effective in disintegrating yeast cell walls. Optimum conditions for autolysis of ruptured yeast cells, obtained with help of response surface methodology (RSM), were pH 7.0, $30^{\circ}C$, ethanol 4% and salt 3%. YA produced by the developed method had significantly higher yield and better sensory quality than that produced by the conventional method.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.253-258
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• 2005

A 3-year-old male lion at Gwangju Uchi Zoo presented for acute onset of haemorrhagic diarrhea and died. The lion showed reddening of the anus as the cause of haemorrhagic enteritis. Necropsy revealed a severe haemorrhagic colitis. Grossly, lesions included icterus, excess pericardial fluid. dark kidneys, and an enlarged, friable liver. The intestines were flaccid, thin-walled, dilated, and 9as-filled. The spleen was enlarged and pulpy because of congestion. Most of organs were rapidly postmortem autolysis. Histopathologically, the intestines were edema and transient leukocyte infiltration of the lamina propria, followed by necrosis. Especially of the intestinal submucosa was edematous, haemorrhagic, or filled with leukocytes. The crypts remained intact or dilated. C perfringens was isolated from a lion at bloody feces, and identified C perfringens type A, confirming the presence of C perfringens $\alpha-toxin$ by PCR. These results were suggested that the case were diagnosed as enterotoxicosis in the lion. More studies are needed on lion enterotoxemia. especially of its etiopathogenesis, in order to develop more efficient prevention for this disease.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.284-292
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• 2015

We explored preprocessing-mediated quality changes in red snow crab fish sauce. A control (C) group and groups treated with autolysis (A), boiling (B), enzymatic hydrolysis (E), and addition of Aspergillus oryzae (K) were formed. The titratable acidity of the K group increased with storage time, whereas that of groups C, A, B, and E decreased. The total and amino nitrogen contents initially increased on storage of all samples, but decreased in later periods. The total plate count (TPC) of the K group was initially 5.26 log CFU/mL and increased to 7.28 log CFU/mL at 3 months of storage. The TPCs of the C, A, B, and E groups were initially <5.00 log CFU/mL and decreased with storage. The lactic acid bacteria count of the K group was initially 4.80 log CFU/mL and increased until month 5 to approximately 6.06 log CFU/mL. The K group scored higher in terms of sensory attributes than the other groups and maintained marketable scores for all relevant properties (color, flavor, off-odor, and overall acceptance). Furthermore, the free amino acid content of the K group was the highest among all groups at approximately 3,000 mg per 100 g. These results suggest that K treatment may be beneficial in the preparation of fermented fish sauce.

• Mycobiology
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• v.41 no.3
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• pp.145-148
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• 2013

Vegetative growth signaling of the opportunistic human pathogenic fungus Aspergillus fumigatus is mediated by GpaA ($G{\alpha}$). FlbA is a regulator of G protein signaling, which attenuates GpaA-mediated growth signaling in this fungus. The flbA deletion (${\Delta}flbA$) and the constitutively active GpaA ($GpaA^{Q204L}$) mutants exhibit enhanced proliferation, precocious autolysis, and reduced asexual sporulation. In this study, we demonstrate that both mutants also show enhanced tolerance against $H_2O_2$ and their radial growth was approximately 1.6 fold higher than that of wild type (WT) in medium with 10 mM $H_2O_2$. We performed quantitative PCR (qRT-PCR) for examination of mRNA levels of three catalase encoding genes (catA, cat1, and cat2) in WT and the two mutants. According to the results, while levels of spore-specific catA mRNA were comparable among the three strains, cat1 and cat2 mRNA levels were significantly higher in the two mutants than in WT. In particular, the ${\Delta}flbA$ mutant showed significantly enhanced and prolonged expression of cat1 and precocious expression of cat2. In accordance with this result, activity of the Cat1 protein in the ${\Delta}flbA$ mutant was higher than that of $gpaA^{Q204L}$ and WT strains. For activity of the Cat2 protein, both mutants began to show enhanced activity at 48 and 72 hr of growth compared to WT. These results lead to the conclusion that GpaA activates expression and activity of cat1 and cat2, whereas FlbA plays an antagonistic role in control of catalases, leading to balanced responses to neutralizing the toxicity of reactive oxygen species.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.105-110
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• 1988

The production of single cell protein using the amylolytic fusant obtained from cell fusion between Hansenula anomala and Saccharomyces cerevisiae was studied. The fusant12 strain was selected for single cell protein production from starchy materials among five fusants. Optimum nitrogen source and its concentration for the growth of fusant12 were ammonium sulfate and 0.1%, respectively. Optimum concentration of soluble starch and optimum pH of the basal medium were lord and pH 5.6, respectively. Autolysis of fusant12 was effectively carried out by addition of 5% (v/v) ethyl acetate to the cell suspension and liquidization for 30 min before incubation for 24 hr at 3$0^{\circ}C$. Coculture of fusant12 and non-amylolytic yeast, Torulopsis candida YA-l5, resulted in the increase of the mass as compared to the monoculture of fusant12. The cell mass on tapioca medium was increased about 2.5 times as on soluble starch medium. The content of crude protein and nucleic acid of the dry cell were 39% and 5.8%, respectively.