• Current Research on Agriculture and Life Sciences
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• v.27
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• pp.21-28
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• 2009

The purpose of this study was to improve the culturability of 'IR 36', a indica type rice cultivar using DNA marker associated with the ability of plant regeneration in anther and seed culture. The culturability of 6 rice cultivars and 2 indica/japonica lines ('MGRI 036', 'MGRI 079') were investigated in anther and seed culture. The culturability of 3 japonica rice cultivars were much higher than tongil and indica rice cultivars, and 'MGRI 036' and 'MGRI 079' has high culturability with 20% regenerability, also. 34 $BC_2F_4$ 4 lines were selected by marker screening using RZ400 among 90 $BC_2F_4$ lines derived from a cross between 'MGRI 079' and 'IR 36'. The frequency of callus formation of 10 $BC_2F_4$ lines were higher than 'IR 36' in anther culture among selected 34 $BC_2F_4$ lines. The ability of plant regeneration of 10 lines were higher than 'IR 36' in the seed culture among selected 34 $BC_2F_4$ lines. A promising line, $BC_2F_4$-28, was selected to have better culturability in the anther and seed culture among selected 34 $BC_2F_4$ lines. The heading date and grain shape of the $BC_2F_4$-28 was similar to 'IR 36'. Using the RZ400 DNA marker associated with the culturability will be useful method for improving of indica rice culticvar's culturability in rice breeding program.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.251-258
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• 2007

Thermal resistance and heat activation characteristics of Clostridium botulinum ATCC 25763 spores were evaluated. The effects of nisin and pH on the activation and subsequent germination were also investigated. Spores of C. botulinum were not inactivated by heat treatments up to $92^{\circ}C$ for 2 hr. Heat treatment at $85^{\circ}C$ for 90 min was selected as the optimal activation condition based on monitoring subsequent germination. L-alanine alone or in combination with L-cysteine was not sufficient to germinate the spores of this strain. Tryptone-Peptone- Glucose-Yeast extract (TPGY) broth supplemented with L-alanine was used as a suitable germination medium. Decreasing pH of activation suspension increased the degree of phase darkening, i.e., germination. In addition, the presence of nisin during activation increased the degree of phase darkening. The majority of spore populations were dormant at a pH of less than 2.8, and these populations required heat activation to increase the culturability on TPGY agar medium. However, extended heating in the presence of nisin at pH 2.8 decreased the spore count; however, heat activation was less necessary at pH 3.4, compared at pH 2.8.

• Journal of Microbiology
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• v.43 no.spc1
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• pp.93-100
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• 2005

It had long been assumed that a bacterial cell was dead when it was no longer able to grow on routine culture media. We now know that this assumption is simplistic, and that there are many situations where a cell loses culturability but remains viable and potentially able to regrow. This mini-review defines what the 'viable but nonculturable' (VBNC) state is, and illustrates the methods that can be used to show that a bacterial cell is in this physiological state. The diverse environmental factors which induce this state, and the variety of bacteria which have been shown to enter into the VBNC state, are listed. In recent years, a great amount of research has revealed what occurs in cells as they enter and exist in this state, and these studies are also detailed. The ability of cells to resuscitate from the VBNC state and return to an actively metabolizing and culturable form is described, as well as the ability of these cells to retain virulence. Finally, the question of why cells become nonculturable is addressed. It is hoped that this mini-review will encourage researchers to consider this survival state in their studies as an alternative to the conclusion that a lack of culturability indicates the cells they are examining are dead.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.918-922
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• 2001

In a previous study, we have isolated a number of lactobacilli from Korean women, and one of them (KLB46) was identified as Lactobacillus crispatus by 16S rRNA gene sequencing. For the ecological treatment of bacterial vaginosis (BV) cell suspension of L. crispatus KLB46 was instillated into BV patients. L. crispatus KLB46 was found to persist for several days in cell suspension with no nutrients. In this study, in order to assess the influence of starvation on physiological activity, we compared the viability and culturability of KLB46 following suspension in various buffer solutions. A pair of in situ fluorescent dye was used to assess viability (i.e. membrane integrity) and the culturability was examined by plate count assay. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit $(BacLight^{TM})$ was applied to estimate both viable and total counts of bacteria in cell suspension. $BacLight^{TM}$ is composed of two nucleic acid-binding stains ($SYTO\;9^{TM}$ and propidium iodide). $SYTO\;9^{TM}$ penetrates all bacterial membranes and stains the cells green while propidium iodide only penetrates cells with damaged membranes, therefore the combination of the two stains produces red fluorescing cells. Optimal staining conditions for $BacLight^{TM}$ were found to be with 0.0835M $SYTO\;9^{TM}$ and 0.05M propidium iodide for 15 min incubation at room temperature in dark. When cells were microscopically examined during 140 hours of starvation, the culturability decreased markedly while the viability remained relatively constant, which suggests that large fraction of KLB46 cells became viable but non-culturable (VBNC) upon starvation.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.527-533
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• 2006

The purpose of this study is to improve the culturability of a indica type rice cultivar, IR 36, using DNA marker associated with the ability of plant regeneration in anther and seed culture. The varietal difference of ability of callus formation and plant regeneration was investigated in anther and seed culture of 8 rice cultivars. Three japonica rice cultivars showed to have better culturability than those of tongil and indica type genotypes. But two indica/japonica lines, 'MGRI 079' and 'MGRI 036', which were selected to have good culturability in previous study showed the highest regenerability (20%) in anther culture of 8 rice cultivars. Thirty four $BC_2F_4$ lines were selected by marker screening using RZ400 for 100 $BC_2F_4$ lines derived from a cross $'MGRI\;079/IR\;36^{^*3}'$. The frequency of callus formation of 30 $BC_2F_4$ lines was higher than those of 'IR 36' in anther culture of the selected $BC_2F_4$ lines. The ability of plant regeneration of 15 lines was higher than that of 'IR 36' in the seed culture of 34 $BC_2F_4$ lines. A promising line, $BC_2F_4-28$, was selected to have better culturability in the anther and seed culture of the $BC_2F_4$ lines. The heading date and grain shape of the $BC_2F_4-28$ was similar to 'IR 36'. In seed culture of 50 $BC_4F_3$ lines derived from a rice cross $'MGRI\;079/IR\;36^{^*5}'$, 11 lines including $BC_4F_3-3$ showed to have higher regenerability compared with 'IR 36'. The highest frequency of plant regeneration (11%) was obtained from $BC_4F_3-46$ in seed culture of the $BC_4F_3$ lines.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.859-862
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• 2004

An isolate of Pseudomonas putida has been found to aggressively colonize root tips and induce plant resistance to Fusarium wilt. However, P. putida mutants lacking Fe-superoxide dismutase (SOD) or both FeSOD and MnSOD activities are less competitive in root tip colonization. In the current study, the growth of an FeSOD mutant was found to be more sensitive than that of the wild-type or a MnSOD mutant to oxidative stress imposed by paraquat treatment and culturing with the soil fungus Talaromyces flavus, which generates reactive oxygen species. Also, the loss of culturability with an aging stationary-phase culture was greater for a double SOD mutant than an FeSOD mutant, while no reduction in culturability was observed with the wild-type and a MnSOD mutant under the same protracted stationary-phase conditions. Accordingly, it was concluded that FeSOD activity is the major form of SOD in P. putida and plays an essential role in survival under stress conditions when increased oxidative stress is encountered.

• Journal of Korean Society of Forest Science
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• v.79 no.2
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• pp.109-114
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• 1990

The axillary buds of 15-year-old Tilia amurensis were cultured on Saito and Ide (IS), Murashige and Skoog (MS) media and woody plant medium (WPM) to establish an effective micropropagation method. Five levels of 6-benzylaminopurine (BAP) were tested. On IS medium and WPM addition of 1.0/l BAP enhanced shoot development and shoot elongation, whereas addition of 0.5/l BAP was effective on MS medium. A better results were obtained from WPM with 1.0/l BAP and MS with 0.1/l BAP. Developed shoots were subcultured on each basal media but with 0.2/l BAP, Multiple shoots were almost doubled in a month. Root formation could be enhanced at higher concentration of indole-3-butyric acid (IBA). Better rooting rate (83.3%) was achieved on a half-strength MS medium with 3.0 /l IBA. Regenerated plantlets were successfully transferred to soil. To investigate the clonal variation in shoot development and shoot elongation by axillary bud culturing, seven plus tree clones were tested, Clonal variation in tissue culturability among plus trees was recognized by the Duncan's multiple range test at the 5% level. Kang Won No. 12 showed the best response on WPM with 1.0/l BAP.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.425-430
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• 1983

Rice (Oryza sativa L.) anthers collected from different genotypes were cultured to investigate the priority to increase callus production rate among several factors affecting on callus formation. Rice varieties, F$_1$ hybrids and F$_2$ plants differed greatly in their abilities to produce callus from anthers, and it was confirmed that the culturability of rice anther was a heritable characteristic. Cold shock treatment before plating anthers promoted callus formation rate, but combined effect with genotype having high culturability was more significant. The response to sucrose concentration in culture medium in callus induction rate was different between rice genotypes, but combined effect with genotype was not significant. Single supplement of NAA to R$_2$ medium increased callus production rate remarkably only in rice genotype having high culturability. Conclusively selection of genotypes is most important to increase callus initiation frequency from rice anthers.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1684-1689
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• 2006

Airborne microorganisms, which are currently termed bioaerosols, have received attention owing to the harmful effects they have on human health. As the concern over airborne microorganisms grows, there also grows an urgent need to study and develop efficient methods for controlling them. In this study, thermal energy using a thermal tube was tested as a control method, mainly against airborne E. coli. For a comparison, B. subtilis var. niger spores were utilized in the experimentation. It was found that the widely known inactivation conditions for microorganisms were not adequate against airborne microorganisms. The experimental results demonstrated the need for extensive studies that should investigate adequate and economic conditions to control against airborne bacteria. In this study, thermal energy exposed by the thermal tube demonstrated an inactivation performance for controlling E. coli bioaerosols.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.45-48
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• 2001

In an effort to optimize tissue culture responses of tall fescue, the effects of basic medium and carbon sources on seed culturability and genotypic difference of plant regenerability were investigated. The MS basal medium was superior to $N_{5}$ 6/ and $B_{medium}$ in enhancing callus growth and plant regeneration. To determine the effect of carbon sources on plant regeneration, the seeds were cultured on medium with 30 g/L sucrose and maltose, respectively. Medium supplemented with 30 g/L sucrose resulted in regeneration of shoots from 50% of the calli. The genotypic difference in plant regenerability was obvious among five cultivars of tall fescue tested. \\`KY31\\` and \\`Hokuryo\\` showed to have higher regenerability with the frequency of 33% and 51%, respectively.