• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.145-157
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• 2000

Cytotoxic substances in dental calculus and root cementum of periodontally diseased teeth inhibit new attachment and regeneration. The purpose of scaling and root planing is to remove pathologic structures harboring these cytotoxic substances in order to create a biologically acceptable root surface. However, these procedures inevitably leave a non-biocompatible smear layer. Conventionally, the smear layer has been removed with low pH etching agents such as citric acid, phosphoric acid and tetracycline hydrochloride(TC). Lately, a supersaturated neutral pH etching solution of ethylene diamine tetraacetic acid(EDTA) has been found to be as effective as low pH etchants with respect to smear removal and to be superior in exposing root surfaceassociated collagen. The aim of the present study was to determine the effect of root surface treatment using EDTA on the initial attachment of human gingival fibroblasts. 27 human teeth, extracted due to severe periodontitis, were cut into dentin slices after root planing. The specimens were divided into TC group(treated with $50㎎/m{\ell}$ tetracycline-HCl, pH 1.52), EDTA group(treated with 17% EDTA, pH 7.4), and non-treated control group. After sterilization, 5th subcultured human gingival fibroblasts were seeded in each culture well containing a prepared root slice and incubated for 15 min., 60 min., and 4 hours in 5% $CO_2$ incubator at $37^{\circ}C$. At each incubation time, the number of attached fibroblasts were counted on the microphotographs taken at a magnification of x100. The difference of the number of attached cells between groups was statistically analyzed by the ANOVA followed by Duncan test in SPSS/PC＋programs. The results were as follows : 1. After incubation for 15 min, the attached cells were significantly more in EDTA group and TC group than non-treated control group(p<0.05), but there was no significance in the difference between EDTA group and TC group(p>0.1). 2. After incubation for 60 min and 4 hours, there was no significant difference in the number of attached cells between all groups(p>0.1). 3. In both EDTA group and TC group, there was no significant difference in the number of attached cells between different incubation(p>0.1). But in control group, the number of attached cells was significantly increased after incubation for 60 min, compared with incubation for 15 min(p<0.05). The above results suggest that root surface treatment using EDTA could enhance the initial attachment of gingival fibroblasts to root surface as effective as tetracycline-HCl.

• Asian-Australasian Journal of Animal Sciences
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• 제1권3호
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• pp.143-147
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• 1988

In order to investigate the mechanism of regulation of progesterone production, quail were hypophysectomized at various times during the ovulation cycle, and granulose cells were isolated from follicles 4 hr after the operation. They were incubated in vitro at $40^{\circ}C$ with or without LH or dibutyryl cyclic AMP, and the amounts of progesterone produced during 3 hr of incubation were measured by radioimmunoassay. Hypophysectomy at 8 hr or 20 hr before the predicted time of ovulation caused a reduced responsiveness of F1 granulosa cells to exogenous LH or dibutyrul cyclic AMP. Although hypophysectomy at 24 hr before ovulation caused a slight reduction of responsiveness of F1 granulosa cells, the reduction of the progesterone production during the incubation without any stimuli was prominent by the sham operation. These results suggest that the presence of pituitary gland influences the ability of the granulose cells to produce progesterone in response to LH or dibutyryl cyclic AMP.

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.17-23
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• 1995

We studied the influence of culture conditions on the acid tolerance of Lactobacillus casei YIT 9018 in artificial gastric juice with respect to relative amount of membrane bound ATPase and their biochemical characteristics. With raising incubation temperature from 30.5$\circ$C to 40.5$\circ$C and lengthening incubation time from exponential phase to late stationary phase, the acid tolerance of L. casei YIT 9018 was increased. As acid tolerance enhanced, C$_{18:1}$ content of membrane fatty acid was reduced and C$_{19:0 cyclo}$ was enriched but the others were not changed greatly. At high ATPase activity, proton permeability was relatively low but this phenomenon did not correspond to acid tolerance. In conclusion, it was considered that changes of C$_{18:1}$ and C$_{19:0 cyclo}$ were closely related to the acid tolerance of L. casei YIT 9018.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.364-367
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• 2005

This study investigated the production of antioxidant from Actinomyces culture supernatant. For the research of the natural marine antioxidant, several bacteria were isolated from the coast of Je-ju in Korea. An actinomycetes strains, S-1 was identified to a genus level 16S ribosomal DNA sequence and fatty acid analysis. From these results and other characteristics described in the Bergey's Manual, this strain was identificated as a Nocardiopsis dassonvillei. Strain S-1 showed high activity of 1,1-diphenyl-2-prcrylhydrazyl radical scavenging. The hydroxyl radical scavenging ability of Nocardiopsis sp. S-1 supernatant was 53%. Nutritional and cultural conditions for the production of antioxidant by this organism under shake-flask conditions have optimized. Similary initial medium pH 7.6, incubation temperature of $25^{\cicr}C$, sodium chloride concentration 2.5 and incubation time of 8 day were found to be optimal.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.276-283
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• 2018

For the first time, polyvinyl chloride (PVC) was used as an easily-handled chlorine source for preparation of isotropic pitch-based carbon fiber (IPCF) incorporating ethylene bottom oil (EO) as a raw material. Pitch precursors were prepared by the chlorination-dehydrochlorination triggered by chlorine radicals originated from PVC; aromatization and poly-condensation reactions occurred by polyene-type radicals from PVC. Radical production and co-carbonization were facilitated by pretreatments of EO through vacuum distillation, bromination, and additional heat treatment. Pitches were prepared by the co-carbonization of pretreated EO and EO containing 20 wt% PVC, and had higher yields and better spinnability than those by simple distillation.

• Mass Spectrometry Letters
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• 제15권1호
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• pp.62-68
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• 2024

The Suspension Trapping (S-Trap) method has been a prominent sample preparation technique since its introduction in 2014. Its capacity to induce protein aggregation using organic solvents has significantly improved protein purification and facilitated peptide identification. However, its full potential for automation has been limited by the lack of a suitable liquid handling system until recently. In this study, we aimed to enhance the automation of S-Trap sample preparation by optimizing the S-Trap digestion process, incorporating triethylammonium bicarbonate (TEAB) and CaCl₂. The utilization of TEAB buffer conditions in this innovative process led to a noteworthy 12% improvement in protein identification. Additionally, through careful observation of various incubation conditions, we streamlined the entire sample preparation workflow into a concise 4 hours timeline, covering reduction, alkylation, and trypsin incubation stages. This refined and expedited automated S-Trap digestion process not only showcased exceptional time efficiency but also improved trypsin digestion, resulting in increased protein identification.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.378-386
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• 2009

A sequential optimization strategy, based on statistical experimental designs, is employed to enhance the production of alkaline protease by a Bacillus pseudofirmus local isolate. To screen the bioprocess parameters significantly influencing the alkaline protease activity, a 2-level Plackett-Burman design was applied. Among 15 variables tested, the pH, peptone, and incubation time were selected based on their high positive significant effect on the protease activity. A near-optimum medium formulation was then obtained that increased the protease yield by more than 5-fold. Thereafter, the response surface methodology(RSM) was adopted to acquire the best process conditions among the selected variables, where a 3-level Box-Behnken design was utilized to create a polynomial quadratic model correlating the relationship between the three variables and the protease activity. The optimal combination of the major medium constituents for alkaline protease production, evaluated using the nonlinear optimization algorithm of EXCEL-Solver, was as follows: pH of 9.5, 2% peptone, and incubation time of 60 h. The predicted optimum alkaline protease activity was 3,213 U/ml/min, which was 6.4 times the activity with the basal medium.

• Macromolecular Research
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• 제11권6호
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• pp.488-494
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• 2003

We have fabricated gelatin-immobilized polyurethane foams (PUFG) by dipping polyurethane foam (PUF) in an aqueous solution containing gelatin and by subsequent reaction with glutaraldehyde after freeze-drying. Gelatin aqueous solutions of different concentrations were used as the dipping solutions to control the amount of immobilized gelatin. The average pore size of PUF decreased with an increase in gelatin concentration. It was found from the hepatocyte adhesion experiment that the amount of hepatocytes seeded on PUFG1, prepared by using a 1% aqueous gelatin solution, was higher than that on other PUFGs. The hepatocytes inoculated in PUFG1, were slightly aggregated as the incubation time increased. The cells inoculated in PUFG1 showed higher ammonia removal ability than those monolayer-cultured on a gelatin-immobilized polystyrene dish (PSG) after 1 and 4 days of incubation time. The inoculated cells exhibited higher albumin secretion relative to monolayer-cultured hepatocytes on PSG. Albumin secretion by hepatocytes seeded on PUFG1 was increased by the presence of serum and was further increased by both the presence of serum and cytokines. The results obtained from a 3-(3,4-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that PUFG can provide a better microenvironment for hepatocyte culture along with nutrition and metabolite transfer through the high porosity of PUF.

• Journal of Plant Biology
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• 제39권2호
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• pp.107-112
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• 1996

To study the compensatory aspect of putrescine biosynthetic enzyme n tobacco suspension cultured cells, we examined the contents of the cellular polyamines and the activities of arginine decarboxylase (ADC, EC 4.1.1.19) and ornithine decarboxylase (ODC, EC 4.1.1.17) in the tobacco suspension cells treated with $\alpha$-difluoromethyl arginine (DFMA) or $\alpha$-difluoromethyl ornithine (DFMO). In the untreated cells, the content of the cellular putrescine was decreased during the first 3 hours and then subsequently increased. However, the content of the cellular spermidine and spermine remained constant during the incubation time. While ADC activity increased after 6 hours, ODC activity decreased following the rapid increase until 6 hours. DFMA induced the decrease in the contents of putrescine and spermidine, and the increase in that of spermine. It also caused the inhibition of ADC and ODC activities throughout the incubation time. DFMO produced the stimulation of ADC activity about 2 times of untreated cells and the decrease in the content of putrescine about 50% of them at 12 hour. The application of putrescine or cycloheximide prevented the increase of ADC activity by DFMO but that of actinomycin-D did not show any detectable effect. The stimulation of ADC activity by DFMO in tobacco suspension cultured cells was probably due to the enhancement of de novo synthesis for ADC protein, which might be regulated in the translation step by the content of the cellular putrescine.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1936-1943
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• 2015

The present study developed an efficient and environmentally friendly method for recovering polyhydroxybutyrate (PHB) from Cupriavidus necator. Several non-halogenated solvents were tested and it was found that butyl acetate and ethyl acetate are powerful solvents for the biopolymer. Testing was performed to examine the effects of temperature (25℃ until temperature below solvent boiling points) and heating incubation time (0-60 min) on the two solvents. Butyl acetate had a higher recovery level (96%) and product purity (up to 99%) than ethyl acetate at 103℃ and a heating incubation time of 30 min. Under these conditions, PHB recorded the highest molecular weight of 1.4 × 10⁶ compared with the standard procedure (i.e., recovery using chloroform). The proposed strategy showed that butyl acetate is a good alternative to halogenated solvents such as chloroform for recovery of PHB.