• Food Science and Biotechnology
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• v.17 no.1
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• pp.123-129
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• 2008

To isolate Bacillus cereus presenting at a level of 5 log CFU/g in kochujang, a primary dilution ($10^{-1}$) of kochujang was heated at $85^{\circ}C$ for 5 min. Two isolated strains Voges-Proskauer positive colony (KBC) and a negative colony (KBM) were identified as B. cereus and Bacillus mycoides, respectively, by biochemical test and 16S rDNA sequencing. $D_{100^{\circ}C}$-Values of KBC and KBM strains was 8.37 and 7.08 min, respectively. When spores of KBC strain were inoculated to kochujang at the level of 4-5 log spores/g, the number of spores was no significant difference (p<0.05) for each sample from 1 up to 60 day of aging. When kochujang was inoculated with 4 log spores/g and heated at $85^{\circ}C$ for 15 min, the number of spores was similar to that of unheated kochujang. Therefore, we estimated that B. cereus isolated from kochujang resistant on the heat treatment ($85^{\circ}C$, 15 min) and its heat resistance characteristics could be used to count the number in kochtjang.

• Biomedical Science Letters
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• v.23 no.2
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• pp.96-103
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• 2017

Nocardia species (spp.) are opportunistic pathogen in immunocompromised hosts. The genus Nocardia contains more than 70 species. Nocardia takedensis has been recently reported as a new species of the genus Nocardia. In this study, we describes the first clinical isolate of N. takedensis from the skin lesion in Busan, Korea. For the identification of clinical isolate to the species level as N. takedensis, classical methods (colony morphology, biochemical characteristics, and antimicrobial susceptibility), molecular method (16S rRNA gene sequencing), and MS (mass spectrometry) analysis were conducted. Clinical isolates grew slowly on the culture media (5% sheep blood agar and chocolate agar) under 5% $CO_2$ condition. Especially, carotene pigmentation was detected well on the media. Using mass spectrometry, Nocardia isolate was not identified to the species level. However, molecular method based on 16S rRNA sequencing confirmed the isolate as N. takedensis correctly. N. takedensis isolate was partial positive for acid-fast bacilli on the Ziehl-Neelsen method. And it was observed to be resistance to amoxicillin/clavulanic acid and ciprofloxacin. Our results provide useful information to develop optimal identification protocol of N. takedensis in clinical diagnostic laboratories.

• Mycobiology
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• v.38 no.3
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• pp.171-175
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• 2010

Metacordyceps yongmunensis is a newly reported species from Korea, which is very similar to Cordyceps species in morphological characters. It grows on large lepidopteran pupa, and numerous white stromata grow on a single host. Mycelial growth characteristics of M. yongmunensis isolates were studied in different media and at different temperatures. Also, different carbon sources, nitrogen sources, and mineral salts were tested for mycelial growth of M. yongmunensis. Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Martin's peptone dextrose agar produced longer colony diameters and more compact mycelial density than other media. The optimum temperature for mycelial growth was $25^{\circ}C$. Carbon sources such as sucrose, soluble starch, dextrose, glucose, dextrin, maltose, and fructose showed better mycelial growth, whereas peptone, yeast extract and tryptone resulted in the best mycelial growth of all of the nitrogen sources tested. All of the mineral salts tested showed similar growth as the control, except $K_2HPO_4$ which showed longer colony diameter and more compact mycelial density. The compact colonies were white and cottony with a greenish margin. The results showed that M. yongmunensis is an easy fungus to growas it grew from 30 to more than 50 mm in 2 wk.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.227-233
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• 2000

Preset study was carried out to evaluate characteristics of lactic acid producing bacteria(LAB) in hen's cecum as probiotics value. Distribution of LAB in intestinal tracts was investigated using 5∼25 weeks - old hens. So, 12 strains to LAB with different morphology were isolated purely. Acid tolerance of LAB tested at pH 1, 2, 3, and 4, and bile resistant also tested at 0, 0.3% and 0.5% bile salt concentration. Growth pattern of LAB observed to 60h. All strains of cecal LAB couldn't survive at pH 1, and decreased linearly survival colony after incubation at pH 2 although some strains could survive for 2h. Most of LAB maintained constant number at pH 3 and 4. The bacterial action could increase linearly at 0% bile salt concentration in all of tested strains. However, only one strain could multiply at 0.3% bile salt, others were influenced by bile salt. That tendency was similar at 0.5% bile salt. Growth was peaked at 12 to 18 h after innoculation. After peak, the decreasing pattern of colony was different to strains which some strains decreased rapidly or maintained for long time. The LAB of hen's cecum was similar to intolerance acidity, but different to resistant to bile salt and growth pattern by strain. So, we choose three strains which have probiocs value, and identified as Lactobacillus amylovorus LLA7, Lactobacillus crispatus LLA9 and Lactobacillus vaginalis LLA11.

• Journal of Veterinary Clinics
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• v.40 no.5
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• pp.323-329
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• 2023

Peripheral blood-derived mesenchymal stem cells (PB-MSCs) have shown promise in cell-based therapy, as they can be harvested with ease through minimally invasive procedures. This study aimed to isolate PB-MSCs from foals and mares and to compare the proliferation and cellular characteristics of the PB-MSCs between the two groups. Six pairs of mares and their foals were used in this study. MSCs were isolated from PB by direct plating in a tissue culture medium, and cell proliferation (population doubling time [PDT], and colony-forming unit-fibroblast assay [CFU-F]), and characterization (morphology, plastic adhesiveness, colony formation, trilineage differentiation) were examined. There was no significant difference in the PB-MSC yield, CFU-F, and PDT between the mares and foals. PB-MSCs from both mares and foals showed typical MSC characteristics in terms of spindle-shaped morphology, plastic adhesive properties, formation of colonies, trilineage differentiation. These results suggest that PB-MSCs isolated from horses, both adult horses, and foals, can be used for equine cell-based therapy.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.69-82
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• 1994

This study was conducted to investigate the physiological characteristics and to isolate plasmid DNA of R. japonicum strains. The results obtained were as follows; Strains S117, S118, 005, 011 and DY-1 were slow-growers and showed alkaline reaction, whereas strains S110, S111, S114, S116, S120 and 010 were fast-growers and produced acid reaction in YEM broth. All the fast- and slow-growing R. japonicum showed gram negative and formed mucous white colony on agar plate. After 7 days, the colonies of the fast-growers were between 2.0 and 4.0mm in diameter, whereas those of slow-growers were approximately between 0.5 and 1.5mm. The fast-growers were uniformly sensitive to the pH of 4.5 and tolerant of the pH of 9.5, whereas the reverse was found for the slow-growers. All the fast-growers were able to grow in the presence of 2% NaCl however the slow-growers were not grown. All the microorganisms grew rapidly in simple mineral salt medium containing as the sole source of carbon. Starch was rarely utilized. All the fast-growers utilized sucrose. The slow-growing R. japonicum strains examined usually contained 1 to 3 plasmid DNA ranging between 15Kb and 250 Kb, whereas the fast-growing R. japonicum strains contained 1 to 3 plasmid DNA ranging from 20 Kb to 250Kb.

• Food Science and Preservation
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• v.23 no.1
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• pp.139-143
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• 2016

This study investigated the effect of electron beam (EB) treatment on the microbial reduction of dried laver (Porphyra tenera) and identified EB-resistant bacteria from the treated dried laver. After EB treatments of 4 kGy and 7 kGy, the numbers of total bacteria and EB-resistant bacteria were measured using tryptic soy agar and mannitol salt agar, respectively. The morphological and biochemical characteristics of each isolated EB-resistant bacteria were investigated and these bacteria were identified. Compared to the control ($1.5{\pm}0.2){\times}10^6CFU/g$, the total bacterial number was significantly decreased to ($5.4{\pm}0.5){\times}10^4CFU/g$ and ($1.1{\pm}0.6){\times}10^4CFU/g$ after EB treatments of 4 kGy and 7 kGy, respectively. With a higher EB dosage, the number of red colonies was almost same, whereas the number of yellow colonies was significantly decreased to ($3.3{\pm}1.2){\times}10^3CFU/g$ and 0 CFU/g for 4 kGy and 7 kGy, respectively. All red and yellow colonies were gram-positive cocci, catalase-positive, and resistant to 3% and 5% NaCl media. From the 16S rDNA sequence analysis, yellow and red colonies were identified as either Micrococcus flavus or M. luteus, with 99% similarity for the yellow colonies, and Deinococcus proteolyticus and D. piscis, with 99% and 97% similarity for the red colonies, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.2
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• pp.58-65
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• 2014

Bumblebees are important pollinators of crops and wildflowers. Bumblebees generally produce one generation per year. One of the key stages for year-round rearing of bumblebees is breaking diapause. To evaluate the effects of a combination method of $CO_2$-narcosis and cold treatment to break the diapause of B. ignitus and B. terrestris queens, we determined whether this method affected their ability to establish a colony after the diapause break. The diapause treatment regimes that were utilized were $CO_2$ ($CO_2$-narcosis), CT-1M (cold treatment at $5^{\circ}C$ for 1 mo), CT-1M-$CO_2$ ($CO_2$-narcosis after cold treatment for 1 mo), CT-2M-$CO_2$ ($CO_2$-narcosis after cold treatment for 2 mo), CT-2M (cold treatment for 2 mo), CT-2.5M-$CO_2$ ($CO_2$-narcosis after cold treatment for 2.5 mo) and CT-2.5M (cold treatment at $5^{\circ}C$ for 2.5 mo). In view of the effects on the colony developmental characteristics of B. ignitus queens, the most favorable diapause treatment was CT-1M-$CO_2$. A combination method of $CO_2$-narcosis and cold temperature treatment yielded better results than that of single $CO_2$-narcosis or cold temperature treatment on the colony development of diapause-broken B. ignitus queens. In the case of B. terrestris queens, we concluded that a combination method of $CO_2$ and cold temperature treatment yielded better results than that of a single cold-temperature (up to 2 mo) treatment. In conclusion, the findings of the present study indicated that the combined application of $CO_2$ and cold temperature was a favorable method for the colony development of diapause-broken B. ignitus and B. terrestris queens compared with only $CO_2$-narcosis or cold temperature treatments. A combination method of $CO_2$ and cold treatment reduced the side effect of $CO_2$-narcosis and shortened the duration of cold treatment by at least 1 mo.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.111-115
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• 2002

To produce yellow pigment selectively, mutants were induced from Monascus anka Nakazawa et Sato IFO 4478 (KCCM 11832 strain), and their characteristics were evaluated. Five kinds of auxotrophic mutants which required amino acids for growth and pigmentation, were isolated through a series of mutagenic treatments. Especially, asparagine auxotroph Y7 produced high ratio of yellow pigment. This mutant showed all the morphological characteristics of Monascuceae but the shape of colony and the diameter of conidia. Mutant Y7 was propagated by sexual reproduction more often than asexual reproduction, which could be effective in production of pigments. Yellow pigment produced extracellularly by the mutant Y7 was more soluble in polar solvents such as ethanol and water than in nonpolar solvents. Its productivity of yellow pigment was 2.2 times higher in the mutant Y7 than in parents. In addition, its yellow pigment showed characteristics of maximum absorption at 373 nm. Moreover, the hue of pigment produced by the mutant Y7 was bright yellow, and it was stable through the subculture over 10 generations.

• Journal of Life Science
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• v.9 no.4
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• pp.395-407
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• 1999

The queens of Korean native bumblebee species, Bombus ignitus were collected from the field in the spring of 1997 and reared under the various temperatures as 15$^{\circ}C$$\pm$1$^{\circ}C$, 2$0^{\circ}C$$\pm$1$^{\circ}C$, $25^{\circ}C$ $\pm$1$^{\circ}C$, 3$0^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and 14L : 10D, to investigate their ecological characteristics, as comparing with control(29$^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and red light). As a result, eggs were laid by foundation queen at 15$^{\circ}C$, but they didn't hatched out while at 2$0^{\circ}C$ eggs were laid by them and they hatched out. When a foundation queen laid eggs at $25^{\circ}C$ and they all were hatched out and normally grown. Finally they were developed to the normal colony. B. ignitus worker survived for 77days at 2$0^{\circ}C$, about 69days at $25^{\circ}C$, about 68days at 3$0^{\circ}C$ and about 63days at 29$^{\circ}C$(control). The first brood workers emerged in 25-27days from the egg which a foundation queen laid. At the various temperatures, the captive queens stand to lay eggs in about 18days at 15$^{\circ}C$, 15days at 2$0^{\circ}C$, 11days at $25^{\circ}C$, 11days at 3$0^{\circ}C$ and 4days in control. The first worker and the first drone from the egg cell of the collected queens appeared in about 27days and 72days at 2$0^{\circ}C$, 26days and 88days in $25^{\circ}C$, 24days and 65days at 3$0^{\circ}C$, 25days and 71days in control, respectively. In colony foundation, 33% of the collected queen at 2$0^{\circ}C$ and $25^{\circ}C$, 100% of the disposed queen at 3$0^{\circ}C$ and in control, and 67% of them at 3$0^{\circ}C$ and in control both produced new queens in 66days and 88days, respectively. The life span of the colony founded covered fro about 3 months at $25^{\circ}C$, 3$0^{\circ}C$ and in control. At lower temperatures, the life span of queen is shorter; 2 months at 15$^{\circ}C$ and 3 months at 2$0^{\circ}C$, respectively. A colony which normally developed, varied in size with rearing temperatures; about 20heads at 2$0^{\circ}C$, 482heads at $25^{\circ}C$, 330heads at 3$0^{\circ}C$ and 452heads in control. A foundation queen monthly oviposited 1.5egg cells at 15$^{\circ}C$, 3.0egg cells at 2 $0^{\circ}C$, 21.7egg cells at $25^{\circ}C$, 42.3egg cells at 3$0^{\circ}C$ and 47.0egg cells in control. As a colony developed in June and July, egg cells as well as daily average cells increased in number, as compared to those in May and August. Also, in June and July, interval(days) of egg laying is shorter than in May and August. Number of nectar pots during the colony development varied with rearing temperatures; 31pots at $25^{\circ}C$, 39pots at 3$0^{\circ}C$, 23pots in control. The emergence of new queen showed a distinctively different two patterns; early emerging type and late emerging type. Workers are rapidly increased from early in July to early in August at $25^{\circ}C$, but at 3$0^{\circ}C$ and in control, emergence of workers are remarkably increased from the middle of June and last until July. No new queen emerged at 15$^{\circ}C$, 2$0^{\circ}C$ and $25^{\circ}C$. New queens at 3$0^{\circ}C$ and in control emerged between late in June and early in July. Thus emergence of new queen was temperature dependent.