• Food Science of Animal Resources
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• v.31 no.2
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• pp.158-165
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• 2011

A sensitive reverse transcriptase-PCR (RT-PCR) method to detect viable Escherichia coli O157:H7 in milk was established. The primer sets were designed based on the nucleotide sequences of the rfbE (per) and wbdN genes in the O157 antigen gene cluster of E. coli O157:H7. RT-PCR using five different primer sets yielded DNA with sizes of 655, 518, 450, and 149-bp, respectively. All five of the E. coli O157:H7 strains were detected by RT-PCR, but 11 other bacterial species were not. The sensitivity of RT-PCR was improved by adding yeast tRNA as a carrier to the crude RNA extract. The RT-PCR amplifying the 149-bp DNA fragment was the most sensitive for detecting E. coli O157:H7 and the most refractory to the bactericidal treatments. Heat treatment at $65^{\circ}C$ for 30 min was the least inhibitory of all bactericidal treatments. Treatment with RNase A strongly inhibited the RT-PCR of heated milk but not unheated milk. This study described RT-PCR methods that are specific and sensitive with a detection limit of 10 E. coli O157:H7 cells, and showed that pre-treating milk samples with RNase A improved the specificity to detect viable bacteria by RT-PCR.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.259-265
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• 2014

Mitochondrial DNA (mtDNA)-depleted (${\rho}^0$) cells are often used as mtDNA recipients to study the interaction between the nucleus and mitochondria in mammalian cells. Therefore, it is crucial to obtain mtDNA-depleted cells with many different nuclear backgrounds for the study. Here, we demonstrate a rapid and reliable method to isolate mammalian mtDNA-depleted cells involving treatment with the antimitochondrial agents ethidium bromide (EtBr) and 2',3'-dideoxycytidine (ddC). After a short exposure to EtBr or ddC, followed by rapid clonal isolation, we were able to generate viable mtDNA-depleted cells from mouse and human cells and were able to successfully repopulate them with exogenous mitochondria from platelets isolated from mouse and human blood samples. These mtDNA-depleted cells can be used to characterize the nuclear mitochondrial interactions and to study mtDNA-associated defects in mammalian cells. Our method of isolating mtDNA-depleted cells is practical and applicable to a variety of cell types.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.102-105
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• 1997

In cultivating human neuroblastoma cells maximum number of neurites per cell and length of the neurite were estimated as 5.5 and 2.2 (nm), respectively It was found that there was correlation between growth and differentiation of nerve cells. Maximum specific BDNF production rate was also calculated as 2.5$\times $10$^{-5}$(ng/cell/day) at 7$\times $ 10$^{5}$ (viable cells/ml) of maximum cell density, corresponding to 100 (ng/mL) of BDNF. The secretion of BDNF was occurred most in the later peroids of the cultivation, yielding 75 (ng/mL) of BDNF. The production of rate of BDNF was elongated in adding 1 ($\mu $g/mL) of BDNF as well as 40% increase of the length of the BDNF. It proves that BDNF can be used as one of biopharmaceuticals to treat age-related diseases such as Alzheimer's disease and Prakinson's disease. It can also provide the information of scaling-up mammalian cell cuture system to economically produce BDNF.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.28-32
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• 2005

Epifluorescence microscopy and direct viable counting methods have shown that only 0.01-0.1% of all the microbial cells from marine environments form colonies on standard agar plates. To culture novel marine microorganisms, high throughput culturing (HTC) techniques were developed to isolate cells in very low nutrient media. This approaches was designed to address microbial metabolic precesses that occur at natural substrate concentrations and cell densities, which are typically about three orders of magnitude less than in common laboratory media. Approximately 5000 cultures of pelagic marine bacteria were examined over the course of 3 years. Up to 14% of cells from coastal seawater were cultured using this method, a number that is 1400 to 140-fold higher than obtained by traditional microbiological culturing techniques. Among the cultured organisms are many unique phylogenetic lineages that have been named as new phyla (7), orders (2, 5, 12), families (3), and genera (1, 4, 6). Over 90% of the cells recovered by this method do not replicate in standard agar plating, the most common method of microbial cell cultivation.

• Archives of Craniofacial Surgery
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• v.21 no.4
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• pp.211-218
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• 2020

Autologous fat grafts are widely used in soft-tissue augmentation and reconstruction. To reduce the unpredictability of fat grafts and to improve their long-term survival, cell-assisted lipotransfer (CAL) was introduced. In this alternative method, autologous fat is mixed and grafted with stromal vascular fraction cells or adipose-derived stem/stromal cells (ASCs). In regenerative medicine, ASCs exhibit excellent therapeutic potential and are also simple to harvest. Although the efficacy of CAL has been demonstrated in experimental and clinical research, studies on its safety in terms of oncologic risk have reported inconclusive results. In order to establish CAL as a viable stem cell therapeutic approach, it will be necessary to demonstrate its oncologic safety in basic and clinical studies. Doing so could transform the paradigm of clinical strategy and practice for the treatment of a wide variety of diseases.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.395-400
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• 2004

Choristoneura fumiferana (Cf-2Cl) insect cells were cultured and immobilized by using cellulosesulfate (NaCS) and polydiallyldimethylammoniumchloride (PDADMAC). A concentration of CfMNPV (Choristoneura fumiferana multiple-mucleopolyhedrovirus) and a Cf-2Cl cell density in the microspheres have been achieved at the densities of $1.57\times10^{10}$ PIBs/ml and $7.5\times10^7$ cells/ml, respectively. Additionally, MTT-test was used to measure the viable cell density in the microspheres, and the confidence of MIT-test was investigated before and after baculovirus infection in the immobilized cell culture.

• Molecules and Cells
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• v.38 no.7
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• pp.610-615
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• 2015

Alveolar epithelial cells have been functionally implicated in Mycobacterium tuberculosis infection. This study investigated the role of ursolic acid (UA)-a triterpenoid carboxylic acid with potent antioxidant, anti-tumor, anti-inflammatory, and anti-tuberculosis properties in mycobacterial infection of alveolar epithelial A549 cells. We observed that M. tuberculosis successfully entered A549 cells. Cytotoxicity was mediated by nitric oxide (NO). A549 toxicity peaked along with NO generation 72 h after infection. The NO generated by mycobacterial infection in A549 cells was insufficient to kill mycobacteria, as made evident by the mycobacteria growth indicator tube time to detect (MGIT TTD) and viable cell count assays. Treatment of mycobacteria-infected cells with UA reduced the expression of inducible nitric oxide synthase, NO generation, and eventually improved cell viability. Moreover, UA was found to quench the translocation of the transcription factor, nuclear factor kappa B (NF-${\kappa}B$), from the cytosol to the nucleus in mycobacteria-infected cells. This study is the first to demonstrate the cytotoxic role of NO in the eradication of mycobacteria and the role of UA in reducing this cytotoxicity in A549 cells.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.87-92
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• 1978

Extensive studies on the commercial fermented milks, which had been distributed over four months from July to October in 1978, were carried out for their microbial characterization including an investigation on the variations of bacterial populations under various storage conditions. 1. Total number of viable cells in the products were in between $5{\times}10^7$ cells/ml and $73{\times}10^7$ cells/ml, and $62{\times}10^7$ cells/ml, however no coliform bacteria were detected in the products. 2. Acidities of the products were not very high but fit in the standard as appeared to be in between 0.4869% and 0.6689%. 3. The acidities of the products showed little changes when stored at $5^{\circ}C$, but rises in 22.55% at $20^{\circ}C$ and in 117.66% at $30^{\circ}C$. 4. Total viable counts weren't varied much upto 96 hours when stored at $5^{\circ}C$, but increased during first 24 hours then decreased gradually at the higher temperatures. 5. Viable counts of lactic acid bacteria were decreased markedly with ascending the storage temperature, showing minimal variations when stored at $5^{\circ}C$.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.299-306
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• 1996

This study was undertaken to examine the effects of fresh ginseng on the physicochemical and microbiological changes in dongchimi juice fermented under various conditions. The pH was somewhat lower in dongchimi juice added with 2.0% and 4.0% of fresh ginseng than that without ginseng, whereas the titratable acidity was higher in dongchimi juice with 2.0% and 4.0% of ginseng addition than the control. The addition of fresh ginseng to dongchimi preparation increased the numbers of total viable bacteria, lactic acid bacteria including Leuconostac mesenterotdes in dongchimi juice during fermentation. The changes in the counts of lactic acid bacteria were similar to those of total viable cells throughout the experiment except the initial stage of fermentation. However, the number of Leucosfastoc mesenternidgs decreased after the palatable stage. Key words : Panax ginseng C.A. Meyer, dongchlmi juice, pH, titratable acidity, microbiological changes.

• Korean Journal of Pharmacognosy
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• v.15 no.1
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• pp.39-42
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• 1984

To examine stability and a separate quantitative method of a mixed preparation of lactic acid bacteria, a capsule containing Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus was suspended and diluted in sterile water. After the diluted suspension was spread on three media of tryptone glucose extract agar, MRS agar and MRS-sucrose agar, their colonies appeared and were counted. The viable counts exceeded the minimum number of the three bacteria and showed that the mixed preparation was stable at least for 18 months. The results also showed that a separate quantitation of viable cells of the each strain was feasible.