• Korean Journal of Microbiology
• /
• v.21 no.4
• /
• pp.185-190
• /
• 1983

Twelve Microorganisms capable of utilizing diaminododecane were isolated from the soil by enrichment culture technique. Seven strains of these were identified as Corynebacterium. The isolated strains were tested for the ability to utilize as carbon source, 10 different kind of alkane derivatives containing CN, $NH_2$, Cl, and SH groups. Laurylcyanide, dicyanooetane, chlorodecane, and dichlorodecane were not utilized by any of the isolated strains; putrescine dihydrochloride, cadaverine dihydrochloride, diaminododecane, and n-dodecane were utilized by all of the isolated strains; and all of the isolated strains except DAD 2-3 could utilize dodecylmercaptan. The alkane derivatives that did not serve as ,growth substrates were tested further in oxidation tests using resting cell preparation. Alkane derivatives that are being oxidized by all of the isolated strains are laurylcyanide and dichlorodecane. Dicyanooctane was also oxidized by all of the isolated strains except DAD 30L, chlorodecane was the only oxidized by the three isolated strains. The most remarkable substrate that is being oxidized is dichlorodecane containing CN groups diterminally. Evidence obtained with thin layer chromatography of ,ethyl acetate extracts of culture broth of isolated strains grown in some alkane derivatives shows that these alkane derivatives are degraded.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.19 no.1
• /
• pp.205-213
• /
• 2009

In order for further systematic maintenance of silkworm stocks kept in Korea we analyzed character quality of a diverse array of silkworm strains originated from several sericulture-practicing countries. The analysis of about ten qualitative characters from 67 strains (13 of Japanese strains, 15 of Chinese strains, 14 of European strains, 6 of Korean and Tropical strains, and 19 of unknown origin) revealed a significant difference in the ten different qualitative characters among silkworm strains. In the analysis of quantitative characters, Japanese and European strains were highest in hatchability, the Korean and Tropical strains were highest in pupation rate, and unknown origin and Chinese strains were highest in cocoon yield and number of egg laid. With the connection of molecular genetic analysis the current data may provide the advanced ground for further systematic maintenance of valuable genetic resources of silkworms, although more breeds should be investigated for further complete pictures.

• Microbiology and Biotechnology Letters
• /
• v.28 no.6
• /
• pp.309-315
• /
• 2000

To isolate yeast strains producing high concentration of ethanol, 125 strains were subjected to screening. Initially 14 strains able to grow in a medium containing 15%(v/v) ethanol, 7 strains capable of growing in a medium containing 50%(v/v) glucose, 23 strains having relatively fast fermentation rates, 13 strains able to grow at $42^{\circ}C$ were selected. After secondary screening, 11 strains having relatively high ini-tial fermentation rate and producing high concentration of ethanol were selected. After tertiary screening 5 strains producing high concentration of ethanol were selected. These 5 strains were again for their ethanol produc-tion, residual sugar, and viability using fermentation medium containing 25% glucose. The strain producing the highest concentration of ethanol was 20-1 strain which produced 10.56%(v/v) ethanol in 4 days, and the highest viable strain was 11-1 which produced 10.35%(v/v) ethanol(13.1%. v/v) with the viability of 30.44% after 5 days of fermentation. Both of the 20-1 and 11-1 strains were identified as Saccharomyces cerevisiae.

• Korean Journal of Food Science and Technology
• /
• v.52 no.6
• /
• pp.678-684
• /
• 2020

The objective of this study was to identify the fermentation characteristics of Bacillus thuringiensis and emetic, non-emetic Bacillus cereus using analytical profile index (API) test. Ten strains of B. thuringiensis and 10 strains of B. cereus including 3 strains of emetic type were used at the same concentrations. The differences of fermentation characteristics between the B. thuringiensis and B. cereus was not obvious, but the differences between the non-emetic and emetic B. cereus were distinctive. Seven among 50 substrates were negative for all non-emetic B. cereus strains and positive for all emetic strains, and three substrates among additional 12 substrates had the same tendency. From these differences, 3 emetic B. cereus strains were not indicated as B. cereus by API test. These results indicate that API test is not a suitable method to identify some strains of emetic B. cereus, and the distinctive differences in substrate utilization can be used to improve selective media.

• Mycobiology
• /
• v.51 no.2
• /
• pp.109-113
• /
• 2023

Auricularia is one of the broadly cultivated edible mushrooms in Korea. Most of the Korean Auricularia strains used for cultivation and breeding are known as A. auricula-judae. Recently, this species has been reported to belong to a species complex. Therefore, this study was carried out to genetically clarify the bred and cultivated Korean A. auricula-judae strains. The internal transcribed spacer (ITS) and IGS1 rDNA region sequences were determined from 10 A. auricula-judae strains by PCR and sequencing. Variation in the nucleotide sequence and sequence length of the two rDNA regions were found among the seven A. auricula-judae strains. A maximum-likelihood (ML) phylogenetic tree based on the ITS sequences clearly placed all the 10 Korean A. auricula-judae strains in the A. heimuer clade of the A. auriculajudae complex. A. heimuer is diverged from A. auricula-judae. An ML phylogenetic tree based on the IGS1 sequences revealed the close relationship between Korean A. heimuer strains to Chinese A. heimuer strains. But each strain could be distinguishable by the IGS1 sequence. Furthermore, progeny strains in the seven Korean strains could be differentiated from their parental strains by the IGS1 sequence based phylogenetic tree. Our results are expected to be used to complement the distinction of domestic Auricularia cultivars.

• Korean Journal of Veterinary Service
• /
• v.21 no.1
• /
• pp.97-104
• /
• 1998

Fugi are eukaryotic, nonphotosynthetic, filamentous or unicellular organisms, most of which grow on nonliving materials as saphrophytes. The majority are therefore opportunistic pathogens and predisposing factors often contribute to the establishment of fungal infection. These include an alteration in the normal flora of the host by prolonged administration of antibiotics, immunosup-pression, concurrent infections, damage to the skin or mucous membranes, constantly moist areas of skin or the exposure to a large infective dose, and as with fungal spores. Fungi may cause a variety of diseases which may be due directly to fungal invasion of tissue or more often to the ingestion of toxins produces by fungi in growing, standing or stored grains and other animals feeds. In this experiment, contaminated fugi were isolated and identified from animal feedstuffs such as Korean cattle, milking cows, pigs and chickens. Twelve genues were isolated from animal feeds, they are 9 from Korean cattle and milking cows feeds, 6 from pigs feeds, and 10 from chickens feeds. Among them, most frequently encountered species was Yeast(56 strains), followed by Fusarium sp(41 strains), Aspergillus sp(20 strains), each of Micorsporum sp and Trichophyton sp(17 strains), Penicilium sp(12 strains), in order. And also minority was isolated as Candide sp(4 strains), Trichoderma sp(3 strains), each of Epidermophytom sp and Absida sp(2 strains), and each of Sporothrix sp and Maduromyces sp(1 strain). Among the Aspergillus sp 20 isolates, A flavus(5 strains), A nidulans(4 strains), A fumigatus(3 strains), A glucans(3 strains), A niger(3 strains) and A terreus(2 strains) were identified.

• Korean Journal of Veterinary Research
• /
• v.43 no.1
• /
• pp.87-94
• /
• 2003

The lytic activity of the set of swine and chicken phages which were derived from lysogenic Staphylococcus hyicus strains of swine and chicken origin was compared by means of S. hyicus isolated from swine, chicken and cattle. Of the 80 strains each from swine and chicken, 71 (88.8%) of strains from swine and all the strains of chicken origin were found to be lysogenic. Swine phages showed wider range of lytic activity to the examined strains than that of chicken phages. Using chicken phages at $100{\times}routine$ test dilution (RTD), 25.0%, 85.6% and 50.0% of swine, chicken and bovine strains were lysed, respectively. However, when the set of swine phages was used at $100{\times}RTD$, higher frequency of the typable strains was found in strains of swine and chicken origin (73.8% and 90.2%). Phage F12 and L16 from chicken set were found to be highly active with chicken and bovine strains. On the contrary, all the swine strains were completely resistant to lysis by the two phages at $100{\times}RTD$. Thirteen (12.5%) of 104 S. aureus strains, 1 (1.8%) of 55 S. simudance strains, 31 (58.5%) of 53 S. chromo genes strains, and none of 31 strains of other coagulase-negative Staphylococcus species isolated from bovine mastitis were typable with the set of swine phages.

• Korean Journal of Veterinary Research
• /
• v.36 no.3
• /
• pp.657-663
• /
• 1996

The API STAPH system was compared with conventional methods for identification of 214 strains of Staphylococcus hyicus subsp. hyicus isolated from cases of exudative epidermitis in piglets, skin of healthy pigs, skin of healthy chickens and bovine intramammary infections, and biochemical characteristics among the swine, avian and bovine strains were also compared. All of the swine and bovine strains produced acid within 24 hours from fructose, lactose and trehalose by conventional methods, but some of the avian strains showed a delayed positive reaction in these carbohydrates. These delayed positive strains in conventional methods gave usually negative results for them in the API STAPH system. With the API STAPH system, eighteen different profile numbers were encountered in 214 strains of swine, avian and bovine origin. The swine and bovine strains, respectively, were distributed among 4 profiles, while the avian strains were distributed among 17 profiles. The profile number observed most frequently in the strains of each animal species was uniformly 6 516 153. By conventional methods, approximately 96% of the swine strains were positive for ${\beta}$-glucuronidase, but not in any strains from chickens and cattle. For hyaluronidase production determined by degradation of sodium hyaluronidate in a solid culture medium, all the swine and bovine strains were positive, but only 37.5% of the avian strains were positive for it. From these findings, there were differences in the production of extracellular active substances between swine strains of Staphylococcus hyicus subsp. hyicus and those isolated from chickens and cattle.

• The Journal of the Korean Society for Microbiology
• /
• v.35 no.2
• /
• pp.129-139
• /
• 2000

Acinetobacter baumannii strains are emerging pathogens of the nosocomial infection with an increasing frequency in recent years. The therapeutic difficulty due to the wide spread of multiple resistant strains was major problem in A. baumannii infection. It seems likely that high frequency of A. baumannii infection will be increasing epidemiological importance in the future. However, the current limited understanding of the epidemiology of A. baumannii infections is caused by lack of a rapid and practical method for the molecular characterization of A. baumannii strains. This study was undertaken to determine molecular types and genetic similarity among A. baumannii strains isolated from four hospitals by RAPD analysis. Eighty-five strains, including 40 from Chunnam University Hospital, 27 from Dankook University Hospital, 15 from Yonsei University Hospital, and 3 from Seonam University Hospital, were classified into three molecular types. Molecular type II was the most common pattern and included 72 strains. All strains from Dankook University Hospital and 40 strains from Chunnam University Hospital belonged to molecular type I or II. A. baumannii strains form Yonsei University Hospital were very distant similarity values. The range of genetic similarity values among 85 strains of A. baumannii was 0.26 to 1.00. Although phenotypes including biotype and antimicrobial resistance pattern of A. baumannii strains were same or very similar to each other, their RAPD patterns were quite different. Typing with phenotypes was found to be less reliable than molecular typing by RAPD analysis. These results suggest that RAPD analysis provides rapid and simple typing method of A. baumannii strains for epidemiological studies. This work is the first epidemiological report of A. baumannii infections in Korea and it is hoped that results of this work may contribute to a better understanding of the clinical importance and epidemiology of A. baumannii strains.

• Korean Journal of Environmental Agriculture
• /
• v.36 no.2
• /
• pp.129-134
• /
• 2017

BACKGROUND: Yeasts are used in a variety of industries. However, most industries are biased toward Saccharomyces cerevisiae ; so we sought to explore non-conventional yeasts (NCY). This study aimed to isolate yeasts from seawater collected from the East Sea of Korea and to analyze the NCY. METHODS AND RESULTS: We first collected seawater and performed pure isolation using four kinds of medium (GPY, DOB + CSM, DG18, and SCG). In total, 314 strains and 17 genera were isolated by ITS sequencing, including Aureobasidum pullulans (236 strains), Cryptococcus (19 strains), Cystobasidium (18 strains), and Rhodotorula (9 strains). Upon in-depth analysis, A. pullulans, the most dominant genus (236 strains), was divided into Group II (147 strains), Unknown I (8 strains), and Unknown II (49 strains). CONCLUSION: In this study, a total of 314 strains were isolated from seawater; many of these yeasts have been found and reported in seawater previously. In-depth analysis of A. pullulans, showed the dominance of Group I (21 strains) and Group II (147 strains) We also discovered Unknown I (8 strains) and Unknown II (49 strains), which have not been reported previously.