• Journal of Microbiology
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• v.42 no.3
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• pp.216-222
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• 2004

In a previous paper, the ogdH gene that encodes 2-oxoglutarat dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-l and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.569-573
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• 2009

The biochemical and microbiological changes of the hard clam shikhae were studied during fermentation at $4-18^{\circ}C$ for 45 days. For preparation of the shikhae, the shucked hard clams were blanched into 2% saline solution and were soaked in seasoning solution before mixing with salt, cooked grain and spices. During fermentation, the initial pH steadily decreased from 5.0 to 4.6, but $NH_2-N$ and VBN concentrations increased to 127 mg/100 g and 27.0 mg/100 g, respectively. Alanine, taurine, glutamic acid, and aspartic acid concentrations increased, but arginine concentration decreased by fermentation. The major organic acids of the fermented shikhae were lactic acid, succinic acid and acetic acid. The major free sugar were maltose, glucose and fructose. The concentration of total viable cell ($2.1\times10^5$ CFU/g) and proteolytic bacteria ($1.2\times10^5$ CFU/g) increased to $4.4\times10^8$ CFU/g and $9.8\times10^7$ CFU/g, respectively until day 15 and then slightly decreased. The concentration of yeast ($2.4\times10^3$ CFU/g) increased to $1.6\times10^7$ CFU/g until day 25, but lactic acid bacteria ($5.0\times10^8$ CFU/g) increased to $5.0\times10^8$ CFU/g until day 9. Vibrio species was not detected on the TCBS agar during fermentation.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1441-1448
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• 2017

Antibacterial compounds are widely used in the treatment of human and animal diseases. The overuse of antibiotics has led to a rapid rise in the prevalence of drug-resistant bacteria, making the development of new antibacterial compounds essential. This study focused on developing a fast and easy method for identifying marine bacteria that produce antibiotic compounds. Eight randomly selected marine target bacterial species (Agrococcus terreus, Bacillus algicola, Mesoflavibacter zeaxanthinifaciens, Pseudoalteromonas flavipulchra, P. peptidolytica, P. piscicida, P. rubra, and Zunongwangia atlantica) were tested for production of antibacterial compounds against four strains of test bacteria (B. cereus, B. subtilis, Halomonas smyrnensis, and Vibrio alginolyticus). Colony picking was used as the primary screening method. Clear zones were observed around colonies of P. flavipulchra, P. peptidolytica, P. piscicida, and P. rubra tested against B. cereus, B. subtilis, and H. smyrnensis. The efficiency of colony scraping and broth culture methods for antimicrobial compound extraction was also compared using a disk diffusion assay. P. peptidolytica, P. piscicida, and P. rubra showed antagonistic activity against H. smyrnensis, B. cereus, and B. subtilis, respectively, only in the colony scraping method. Our results show that colony picking and colony scraping are effective, quick, and easy methods of screening for antibacterial compound-producing bacteria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.356-361
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• 2007

Recently, the development of various culture-independent identification techniques for environmental microbes has greatly enhanced our knowledge of microbial diversity. In particular, denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments, generated using the polymerase chain reaction (PCR) is frequently used to examine the diversity of environmental bacterial populations. This method consists of direct extraction of the environmental DNA, amplification of the 200-600 bp 16S rDNA fragments with universal primers, and separation of the fragments according to their melting point on a denaturing gradient gel. In this study, we investigated the seaside microbial community in coastal areas of Busan, Korea, using culture-independent techniques. First, marine genomic DNA was extracted from seawater samples collected at Songjeong, Gwangahn, and Songdo Beaches. Then, PCR was used to amplify the bacterial 16S rDNA using universal primers, and DGGE was used to separate the amplified 500 bp 16S rDNA fragments. Finally, the tested 16S rDNA genes were further analyzed by sequencing. Based on these experiments, we found that DGGE analysis clearly showed variation among the regional groups. It can be used to monitor rapid changes in the bacterial diversity of various environments. In addition, the sequence analysis indicated the existence of many unculturable bacteria, in addition to Arcobacter, Pseudoaltermonas, and Vibrio species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.666-674
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• 2012

We examined the cause of a disease outbreak in adult olive flounder Paralichthys olivaceus, which occurred at a Korean aquaculture farm in Korea in 2011. The principal signs included an expanded abdomen and congested liver, with persistent mortality (a little over two months). At the beginning of the outbreak, farm administrators misjudged the disease as bacterial in origin, because of the aforementioned signs, persistent mortality, and the detection of bacterial species, including Vibrio spp. and Streptococcus spp. Moreover, the detection of viral hemorrhagic septicemia virus (VHSV) by reverse trasnscription-PCR analysis was complicated by use of the VHS-VN primer set, which has been in general use recently, because it produced weak bands in some samples. Therefore, we recommend the use of at least two different primer sets in the diagnosis of VHSV. Our histopathological findings indicate that necrotizing myocarditis could be considered a pathogenic sign of VHSV infection.

• Korean Journal of Microbiology
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• v.36 no.1
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• pp.74-78
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• 2000

Vibrio, Photobacterium, Alteromonas and Xenorhabdus species are capable of emitting light, called bioluminescence. They exist in marine, freshwater and terrestrial environments. Bacterial bioluminescent reaction is that reduced riboflavin phosphates and a long-chain aldehyde are oxidized in the presence of molecular oxygen and enzyme luciferase. This experiment aims to develop the proper culture media and to optimize the storage condition for the recovery of bioluminescent activity in Photobacterium phosphoreum. The Luria broth (LB) medium was modified for cultivation of Photobacterium phophoreum, called as modified LB(mLB) medium. The mLB medium is LB fortified with 3% glycerol and 1.5% NaCl. In mLB medium. bacterial growth and bioluminescent activity are 25% higher than those in a Nutrient broth medium. When the cell stocks were stored at $-20^{\circ}C$, $-70^{\circ}C$ and LN2 for 3 months, cell growth and bioluminescent activity of culture after stored at $-20^{\circ}C$ were better than those of other treatments. The highest bioluminescent activity obtained at the late exponential phase in all treatments. When the cell stock was freeze-dried with 5% adonitol as a cryoprotectant, the recovery of cell was better than those of control and freeze-dried cell stock without addition of cryoprotectant.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.315-319
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• 1996

The yields of methanol extracts of several Chrysanthemum spp.(5 species, 9 parts) and their solvent fractions were investigated. The yields of methanol extracts ranged from 16.9%(for flower of C. indium, Cultivated) to 31.5%(for whole plant of C. indium). In the tests of the antibacterial activity. the methanol extracts from flower of C. zawadskii and C. boreale, whole plant of C. zawadskii, and flower of C. coronarium showed excellent antibacterial activity. Generally, the chloroform fractions exhibited stronger antibacterial activity against all the bacteria tested when compared with other solvent fractions. In case of C. boreale, the chloroform fraction of the whole plant was shown stronger antibacterial activity against all four bacterial strains tested when compared with that of the flower. The chloroform fractions from flower and whole plant of C. boreale and C .zawadskii, and flower of C. coronarium were shown a similar TLC pattern.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.17-25
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• 1979

Bacteriologic diagnosis of enteric infection remains to be an important role of clinical laboratory because of the prevalence of the infection. Often the determination of etiologic agent and its susceptibility to antibiotics are of vital importance for a proper management of the infection. In our previous paper, an analysis of the isolation of enteric pathogens for the years 1969-73 was reported to clarify the status of those years. The present analysis was made based on the data obtained during the years 1974-78, to see if any change of the status was rendered. 1. During the 5-year period, from the cultures of 7,308 stool or rectal specimens 833 patients yielded enteric pathogens: 468 Shigella, 295 Salmonella, 30 Vibrio parahaemolyticus and 40 enteropathogenic Escherichia coli(EPEC). 2. Of the 295 Salmonella, 271 were S. typhi Isolation of 12 S.paratyphi-A, 1 Salmonella group B, 4 group C, 5 group D and 2 group E meant a definite increase of these sero-groups, S. typhi was most frequently isolated in August and in December, and from 30- to 39-year-old patients. 3. Of the 468 Shigella, 10 were subgroup A, 338 subgroup B, 3 subgroup C and 117 subgroup D. Most of the subgroup B belonged to type 1,2, or 3. The proportion of S. sonnei decreased from 31.3% in 1974 to 18.2% in 1978. In foreign patients, S. sonnei remained to be the frequntly isolated species. Shigella isolation was frequent in August and in 2- to 5-year-old patients. 4. V. parahaemolyticus was isolated from 30 and EPEC from 40 patients. 5. Ninty-nine per cent and 99.5% of the S. typhi isolates were susceptible to chloramphenicol and to ampicillin respectively. 92.8% of S sonnei were susceptible to ampicillin. S. flexneri type 2 was notable for their markedely decreased proportion being susceptible to ampicillin: 84.4% in 1974 and 25.6% in 1978.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.241-246
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• 2012

This report outlines the development of a rapid, simple, and sensitive detection system for pathogenic bacteria using a capillary electrophoresis-based, single strand conformation polymorphism (CE-SSCP) combined with PCR. We demonstrate that this method, used with primers targeting the V4 region of the16S rRNA gene, is capable of the simultaneous detection of 10 microbes that could be associated with foodborne illness, caused by animal-derived foods: Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7, Campylobacter jejuni, Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Yersinia enterocolitica, Vibrio parahaemolyticus, and Enterobacter sakazakii. The traditional detection techniques are time-consuming and labor-intensive, due to the necessary task of separate cultivation of each target species. As such, the CE-SSCP-PCR method, that we have developed, has the potential to diagnose pathogens rapidly, unlike the traditional technique, in order to prevent foodborne illness in a much more efficient manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.885-891
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• 1996

Various problems in fermented fish products have been a major obstacle to manufacture the product in large scale, which is mainly concerned with the food safety. In this review, salt-fermented anchovy was selected to elucidate the characteristics of microorganisms involved in fermentation; thereby, it is suggested for research areas to achieve the quality improvement of tile product. Different microorganisms were involved in fermentation of anchovy. Dominant species were reported to be Bacillus sp., Pseudomonas sp., and Micrococcus sp., other microorganisms were Vibro sp., Clostridim sp., Serratia sp., Achromobacter sp., Streptococcus sp., Breuibacterium sp., Halobacterium sp., Flavobacterium sp., Corynebacterium sp., Acinetobacter sp., Sarcina sp., Staphylococcus sp., Torulopsis sp., and Saccharomyces sp. To standardize the quality of fermented fish products, screening and isolation of promising microorganisms should be carried out to develop different types of products; at the same time, proper sanitation control should be employed to keep the commercial value of the product by prolonging the shelf life.