• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.134-151
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• 2024

Salmonella spp. is among the most important water-borne and food-borne pathogens and is one of the most common causes of human gastroenteritis and diarrheal diseases globally. In this study, Salmonella spp. isolated from food, environmental samples, and patients with food poisoning or diarrhea were investigated Salmonella serovars, antibiotic resistance using Vitek2, and genetic characteristics through pulsed-field gel electrophoresis (PFGE). Salmonella spp. of 339 strains, including 26 strains from food or environmental samples and 313 strains from patients, were isolated from Jeju Island of South Korea between 2020 and 2023. The monthly number of isolated Salmonella spp. gradually increased from March, with the highest number being in August. No significant differences in Salmonella spp. isolated from patients according to gender was observed. However, Salmonella spp. was most frequently isolated from people aged 70 years or older and least frequently isolated from those between ages 10 and 19 years. Salmonella spp. isolated from food or environmental samples were distributed among eight different serovars and the main serovars were identified in the order of S. Bareilly (26.9%), S. Rissen (23.1%), and S. Thompson (19.3%). Salmonella spp. isolated from patients were distributed among 27 different serovars and the main serovars were identified in the order of S. Bareilly (31.0%), S. Typhimurium (24.6%), and S. Enteritidis (11.5%). The main cause serovars of Salmonella spp. outbreaks are S. Bareilly, S. Enteritidis, S. Thompson. Antibiotic resistance tests indicated resistance to various antibiotics and some Salmonella spp. exhibited multidrug resistance. Salmonella spp. showed various genetic correlations among the 17 serovars. These results indicate that they can be used as basic data for epidemiological investigations by predicting the appearance of Salmonella spp. and providing a scientific basis.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.102-108
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• 2024

This study was performed to establish the epidemiological features of a food poisoning outbreak that occurred in the cafeteria of a company in Chungcheongnam-do Province, Korea, in October 2020, and to recommend measures to prevent similar outbreaks. Twenty-one patients with acute gastroenteritis, three food handlers, seven cooking utensils, and 12 preserved food samples were subjected to viral and bacterial analyses based on procedures described in the "Manual for Detection of Foodborne Pathogens at Outbreaks". Among 135 individuals who had been served the meals, 21 (15.6%) showed symptoms of nausea and vomiting within an hour of consuming the food. Bacillus cereus were isolated from 11 (52.4%) of the 21 patients, one food service employee, one item of cooking ware, and 12 preserved food samples. In addition, we confirmed the toxin genes CER, nheA, and entFM from the isolated B. cereus strains. Pulsed-field gel electrophoresis results indicated that all of the isolated B. cereus strains were closely related, with the exception of strains obtained from one patient and one sample of preserved food. These findings provide evidence to indicate that the isolated B. cereus originated from preserved foods and an unhygienic eating environment. This outbreak highlights that the provision of food in non-commercial food systems must be thoroughly managed. In addition, it emphasizes the necessity for the correct and timely identification of causal pathogens for tracing the cause of food poisoning outbreaks, and the need to preserve food under appropriate conditions. To prevent similar cases of food poisoning, it is necessary to investigate cases based on an epidemiological approach and share the findings.

• Food Science and Preservation
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• v.30 no.5
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• pp.885-895
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• 2023

This study aims to investigate the production and characteristics of protein hydrolysates derived from tuna byproducts (TP) using various proteolytic enzymes and to compare the antioxidant activity of the resulting hydrolysates. The TP were subjected to enzymatic hydrolysis using five different proteases: alcalase, bromelain, flavourzyme, neutrase, and papain, and the antioxidant activities of the hydrolysates were evaluated. Subsequent analysis of the available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns indicated a high degree of hydrolysis in TP after treatment with all the enzymes, except for papain. Based on the RC₅₀ values obtained from four different antioxidant analyses, all the hydrolysates exhibited similar antioxidant activity, except for the flavourzyme hydrolysate, which showed significantly higher scavenging activity against ABTS radicals and hydrogen peroxide than the other hydrolysates. These findings suggest that protein hydrolysates derived from TP hold promise as potential sources of natural antioxidants.

• Animal Bioscience
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• v.37 no.6
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• pp.1096-1109
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• 2024

Objective: This research aims to explore the nutritional and bioactive peptide properties of goat meat taken from various primal cuts, including the breast, shoulder, rib, loin, and leg, to produce these bioactive peptides during in vitro gastrointestinal (GI) digestion and absorption. Methods: The goat meat from various primal cuts was obtained from Boer goats with an average carcass weight of 30±2 kg. The meat was collected within 3 h after slaughter and was stored at -80℃ until analysis. A comprehensive assessment encompassed various aspects, including the chemical composition, cooking properties, in vitro GI digestion, bioactive characteristics, and the bioavailability of the resulting peptides. Results: The findings indicate that the loin muscles contain the highest protein and essential amino acid composition. When the meats were cooked at 70℃ for 30 min, they exhibited distinct protein compositions and quantities in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, suggesting they served as different protein substrates during GI digestion. Subsequent in vitro simulated GI digestion revealed that the cooked shoulder and loin underwent the most significant hydrolysis during the intestinal phase, resulting in the strongest angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition. Following in vitro GI peptide absorption using a Caco-2 cell monolayer, the GI peptide derived from the cooked loin demonstrated greater bioavailability and a higher degree of ACE and DPP-IV inhibition than the shoulder peptide. Conclusion: This study highlights the potential of goat meat, particularly cooked loin, as a functional meat source for protein, essential amino acids, and bioactive peptides during GI digestion and absorption. These peptides promise to play a role in preventing and treating metabolic diseases due to their dual inhibitory effects on ACE and DPP-IV.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.28-32
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• 2007

Purpose : Human angiotensin converting enzyme (ACE) gene shows an insertion/deletion polymorphism in 16 intron, and three genotypes are determined by whether a 287 bp fragment of the DNA is present or not; II, ID and DD genotype. DD genotype has been suggested as a risk factor of chronic nephrotic disease such as IgA nephropathy and diabetic nephropathy, various cardiovascular diseases and several other diseases. ACE activity increases in acute hepatitis, chronic persistent hepatitis, chronic active hepatitis and cirrhosis. On the other hand, patients with fatty livers have normal ACE activity. This study was designed to find out the relation between polymorphsims of the ACE genes and neonatal hyperbilirubinemia in Koreans. Methods : The genomic DNA was isolated from 110 full-term Korean neonates who had hyperbilirubinemia with no obvious causes (serum bilirubin$${\geq_-}12mg/dL$$) and 164 neonates of a control population (serum bilirubin <12 mg/dL). We performed polymerase chain reaction (PCR) to see the allele of the ACE gene. Electrophoresis was done in the PCR products in 1.5 percent agarose gel, and then DNA patterns were directly visualized under ethidium bromide staining. Results : ACE genotypes in the hyperbilirubinemia group are as follows; 26.36 percent for II, 53.64 percent for ID, 20.00 percent for DD, 0.532 for I allele and 0.468 for D allele. These distributions were not significantly different from those in the control group; 24.39 percent for II, 51.83 percent for DI, 23.78 percent for DD, 0.503 for I allele and 0.497 for D allele. Conclusion : In this study, ACE gene polymorphism was detected in the neonatal hyperbilirubinemia and control group. The most frequent genotype was ID. Our results indicate that the ACE gene polymorphism is not associated with the prevalence of neonatal hyperbilirubinemia in Koreans.

• Journal of Life Science
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• v.18 no.2
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• pp.264-272
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• 2008

The lactate dehydrogenase (EC 1.1.1.27, LDH) isozymes in tissues from Acanthogobius hasta were characterized by biochemical, immunochemical and kinetic methods. The activities of LDH in skeletal muscle and eye tissues were 65.30 and 53.25 units, but LDH activities in heart and liver tissues were very low. LDH/CS (EC 4.1.3.7, citrate synthase) in skeletal muscle was the highest as 22.29. Specific activities of LDH in brain, eye and skeletal muscle were 56.45, 38.04 and 11.0 units/mg, respectively. The LDH isozymes in tissues were separated by polyacrylamide gel electrophoresis after immunoprecipitation with antiserum against $A_4,\;B_4$ eye-specific $C_4$ and liver-specific $C_4$. LDH $AC_4$ isozymes were detected predominantly in skeletal muscle, brain and eye tissues, and $B_4$ isozyme was detected in heart. Anodal eye-specific $C_4$ and cathodal liver-specific $C_4$ were coexpressed in A. hasta. The eye-specific $C_4$ isozyme showed higher activity in eye tissue, but liver-specific $C_4$ isozyme showed lower activity in liver. As a result, one part of molecular structures in $A_4\;and\;C_4,\;A_4\;and\;B_4$, and eye-specific $C_4$ and liver-specific $C_4$ were similar, but in $B_4\;and\;C_4$ were different with each other. Therefore the subunit A may be conservative in evolution, and the evolution of subunit B seems to be faster than that of subunit A. The LDH $A_4$ isozyme of skeletal muscle was purified in the fraction from elution with NAD+ containing buffer of affinity chromatography and eye-specific $C_4$ isozyme was eluted right after $A_4$, so the structure of eye-specific $C_4$ isozyme is similar to $A_4$. And LDH activity remained 35.22-43.47% as a result of the inhibition by pyruvate, the Michaelis-Menten constant values for pyruvate was 0.080-0.098 mM, and Vmax were 153.85 units, 35.09 units in skeletal muscle and eye, respectively. Also the $B_4$ isozyme was the thermo-stablest and $C_4$ was stabler than $A_4$ isozyme. The optimum pH of LDH was 6.5. The results mentioned above indicate that isozymes in tissues showed the properties between LDH $A_4\;and\;B_4$ isozyme as A. hasta was adapted to hypoxic conditions. Also LDH seems to function more effectively under anaerobic condition because LDH in skeletal muscle and eye tissues have high affinity for pyruvate.

• The Korean Journal of Mycology
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• v.6 no.2
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• pp.1-10
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• 1978

In de novo biosynthesis of the extracellulor enzymes-proteinsaes, alpha and gluc-amylases during the synchronized differentiation of Aspergillus niger in submerged culture and surface liquid culture were investigated. Gluc-amylase was synthesized in the stage of presporulation in which phialide formation is involved. Proteinase was synthesized both in the stages of conidiophore formation and presporulation. Alpha-amylase was synthesized during presporulation and sporulation stages, the activity of enzyme lasted for seven days on surface liquid culture. It seemed that the synthesis was occured in de novo partly repressed by the catabolite, and its nature was found to be constitutive since it is produced in non-starch medium. Polyacrylamide gel electrophoresis have shown that presporulating and sporulating body produced diverse types of the proteins whereas the earlier stages of vegetative body showed simpler profiles. The uptake of C-14 uracil into RNA and C-14 glutamate into protein were shown to be vigorous in presporulating body rather than those in sporulating body. Coincidence of alpha-amylase biosynthesis in de novo and sporulation may be significant in the study of differentiation in which gene expression is involved.

• Journal of Dairy Science and Biotechnology
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• v.27 no.2
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• pp.7-16
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• 2009

Appenzeller cheese samples were prepared by addition of 0.5, 1.0, and 2.0% green tea (Camellia sinensis, CS) powder and control cheese. We examined various quality characteristics of the novel cheese, such as viable-cell counts, pH, water-soluble nitrogen (WSN), non-casein nitrogen (NCN), non-protein nitrogen (NPN), and catechin level during maturation for 16 weeks at $14^{\circ}C$. To develop a Korean natural cheese containing green tea powder, we also analyzed the changes in the polyacrylamide gel electrophoresis pattern, chemical composition, and sensory qualities. The viable cell counts of the samples were not significantly different. Until the $3^{rd}$ week, the pH of the CS cheese decreased with an increase in the maturation time. However, the pH gradually increased by the $12^{th}$ week, while WSN, NCN, NPN also increased. The WSN, NCN, NPN, and catechin values for the CS cheese samples were significantly higher than the values for the control cheese. The polyacrylamide gel electrophoretic pattern of caseins for the CS cheese indicated that this cheese degraded more rapidly than the control cheese did. In the sensory evaluation, cheese with 1.0% CS powder showed the highest scores in taste and appearance and good scores in flavor and texture. These results indicate that 1.0% CS is the optimal value for addition to cheese, and cheese containing 1.0% CS shows good physiological properties and reasonably high overall sensory acceptability.

• The Journal of the Korean Society for Microbiology
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• v.17 no.1
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• pp.21-34
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• 1982

One hundred and twenty-one strains each of Escherichia coli isolated from stools of 60 patients who received various antimicrobial drugs in hospital for more than one week and apparently healthy 60 students who have no history of taking antimicrobial drugs during recent one month, were tested for their resistance to 13 antimicrobial drugs. The frequency of resistance strains was highest to tetracycline with 69.2%, and followed by streptomycin(Sm), sulfisomidine(Su), chloramphenicol(Cm), ampicillin(Ap), and carbenicillin(Cb) in the decreasing order, ranging from 61.2% to 39.3%. Strains resistant to kanamycin(Km), cephaloridine(Cr), and trimethoprim(Tp) occupied about one-fourth of strains, and only four strains were resistant either one or more of nalidixic acid, gentamicin and amikacin, and no strain was resistant to rifampicin. The frequency of resistant strains to Cm, Ap, Km, Cr, and Cb was much higher among patient isolates than student strains, but strains resistant to the other drugs showed almost the same frequencies between patient and student isolates. There was a marked difference in average minimum inhibitory concentrations of between resistant and susceptible strains, suggesting that the resistance to drugs is the plasmid origin. Seventy-six percent of strains were resistant to one to 10 drugs tested, and no much difference was observed between strains from patients and students. However, strains resistant to four or more drugs were much more frequently found among patient isolates than student strains, with the increasing tendency of multiply resistant strains among patient isolates following the increase in the number of resistant drugs. The transfer of drug resistance by conjugation was tested and 98 strains(67.5%) among 145 which were resistant to two or more drugs were found to transfer their drug resistance to E. coli. Among 74 strains resistant to 7 or more drugs, all except one transferred the resistance, and the number of strains with transferable resistance decreased, as the number of resistant drugs decrease. A R plasmid from randomly selected p13 strain was tested for the incompatibility group, and the plasmid was classified into Inc F II. R plasmM DNA bands were identified by polyacrylamide gel electrophoresis.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.31-43
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• 1997

This study was carried out to investigate classfication of weedy rice (Oryza sativa) based on isozymes esterase and peroxidase, growth and developmental difference of weedy rices and rices grown under dry and water condition, and weedy rice control and tolerant difference of weedy rices in various herbicides using weedy rices collected from thirteen strains of Chonnam, one Chonbuk, two Kyeongki and two rice cultivars. 1. The collected weedy rices were classified into three groups based on isozyme esterase and peroxidase using polyacrylamide gel electrophoresis(PAGE) method. The classified groups were not same each other. 2. Plant height was taller in collected weedy rices than rice cultivars at 18 days after seeding under dry and water conditions, but number of leaves, shoot fresh weight, root fresh weight and root length were not significantly different between collected weedy rices and rice cultivars. In addition, growths of collected weedy rices were greater in dry- than water-condition. 3. After thiobencarb(S-4-chlorobenzyl diethythiocarbamate), molinate(S-ethyl hexahydro-1H-azepine-1-carbothioate) and oxadiazon(5-tert-butyl-3(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2-one) were applied at 6 days before seeding, the weedy rices controlled 100% by thiobencarb at 2.1kg ai/ha and 024kg ai/ha oxadiazon treatment but controlled 26% to 67% by molinate at 6.5kg ai/ha. Rice due to the herbicides was injured severely(25% to 100%) in flood condition at time of rice seeding after oxadiazon at 0.48kg ai/ha and 2.1kg ai/ha thiobencarb application, except for molinate which injured rice slightly(4% to 13%) in drain condition. The collected weedy rices to all experimented herbicides showed slight intraspecific variations. The intraspecific variations of weedy rices decreased in the order of thiobencarb>molinate>oxadiazon.