• Asian-Australasian Journal of Animal Sciences
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• 제25권10호
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• pp.1381-1388
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• 2012

An in vitro experiment was conducted to examine the effects of defaunation (removal of protozoa) on ruminal fermentation characteristics, $CH_4$ production and degradation by rumen microbes when incubated with cereal grains (corn, wheat and rye). Sodium lauryl sulfate as a defaunation reagent was added into the culture solution at a concentration of 0.000375 g/ml, and incubated anaerobically for up to 12 h at $39^{\circ}C$. Following defaunation, live protozoa in the culture solution were rarely observed by microscopic examination. A difference in pH was found among grains regardless of defaunation at all incubation times (p<0.01 to 0.001). Defaunation significantly decreased pH at 12 h (p<0.05) when rumen fluid was incubated with grains. Ammonia-N concentration was increased by defaunation for all grains at 6 h (p<0.05) and 12 h (p<0.05) incubation times. Total VFA concentration was increased by defaunation at 6 h (p<0.05) and 12 h (p<0.01) for all grains. Meanwhile, defaunation decreased acetate and butyrate proportions at 6 h (p<0.05, p<0.01) and 12 h (p<0.01, p<0.001), but increased the propionate proportion at 3 h, 6 h and 12 h incubation (p<0.01 to 0.001) for all grains. Defaunation increased in vitro effective degradability of DM (p<0.05). Production of total gas and $CO_2$ was decreased by defaunation for all grains at 1 h (p<0.05, p<0.05) and then increased at 6 h (p<0.05, p<0.05) and 12 h (p<0.05, p<0.05). $CH_4$ production was higher from faunation than from defaunation at all incubation times (p<0.05).

• 한국환경농학회지
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• 제31권2호
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• pp.104-112
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• 2012

논 생태계를 모의하여 토양에 투입된 비료의 종류(AS, PMC, HV)와 토양 수분 변동조건(습윤기간, 전이기간, 건조 기간)으로 구분하여 $CH_4$과 $CO_2$ 플럭스를 조사하였다. $CH_4$ 플럭스는 0~13.8 mg $CH_4$/m/day의 범위에서 변화하였으 며, 시기적으로 습윤기간 초기와 전이기간과 건조기간 경계 시점에서 높은 값을 보였다. $CO_2$ 플럭스는 습윤 초기에 최대 치를 보이고 지속적으로 감소하다가 전이기간에 다시 상승하 였다. 최종토양의 탄소함량 변화는 대조구에서-5.4%이었고, 비료 처리구에서는-7.5~-16.4%이었다. HV 시용은 타 비종 에 비해 $CH_4$과 $CO_2$ 플럭스를 증가시켰는데, 이는 녹비작물 이 가축분 퇴비에 비해 상대적으로 이분해성으로 배양 초기 에 유기물 분해에 의해 $CH_4$과 $CO_2$ 발생량이 높았기 때문이 다. AS나 PMC 처리구에서 $CH_4$ 플럭스가 대조구에 비해 낮았는데, 이는 AS의 ${SO_4}^{2-}$와 퇴비에 함유된 산화형 물질($Fe^{3+}$, $Mn^{4+}$, ${NO_3}^-$)과 같은 전자 수용체에 의해 습윤기간 중 이들 물질이 전자수용체로 활용되어 $CH_4$ 생성이 감소할 수 있음 을 의미한다. PMC와 HV의 탄소 손실률을 비교하면, HV와 같은 이분해성 유기물에 비해 PMC와 같은 난분해성 유기물 의 시용이 토양 탄소량을 증가시키는 것으로 나타났다. 또한, 본 연구는 HV와 같은 녹비 작물이 질소 공급의 측면에서 화 학비료를 대체할 수 있지만, 화학비료 시용에 비해 $CH_4$ 발생 이 증가할 수 있음을 제시한다. 따라서, 이분해성 유기물(녹비 작물)과 난분해성 유기물(가축분퇴비)을 혼합 시용할 경우 양 분공급과 탄소저장량 증대에 모두 유리할 것으로 기대된다.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.109-120
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• 2022

This study has incorporated the mechanics-dynamics-emotions (MDE) and two behavioral learning paths to investigate the customers' co-creation behavior in Taiwan. The intuitive path begins with a gamification design that reflects the customers' proactive and innovative behavior; the cognitive path begins with persuasion knowledge remarks based on rational and reactive reasoning. These two paths conclude what forms user co-creation. The study collects data of 505 active social media users in Taiwan and employs structural equation modeling. The empirical findings demonstrate persuasive knowledge and gamification design are significantly associated with self-reference, and in turn, positively associated with co-creation. It indicates that cognitive behavior plays the main role in forming co-creation. Participants are more drawn to co-creation behaviors by the marketing contents that prompt reactive behaviors than proactive ones. Therefore, marketing managers can use appropriate stimuli to enhance co-creation behavior. Companies can design activities related to users, and more accessible for reactive, instead of proactive behavior, i.e., asking for their initiatives. It also suggests that companies' marketing campaigns should involve key opinion leaders matching the product image and the target audience's preferences. The novelty of this study is to introduce a novel augmented MDE framework to extend the "dynamics" into the incubation and implementation stage.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.319-328
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• 2023

Malassezia and Staphylococcus are the most dominant genera in human skin microbiome. To explore the inter-kingdom interactions between the two genera, we examined the transcriptional changes in Malassezia and Staphylococcus species induced upon co-culturing. RNA-seq analyses revealed that genes encoding ribosomal proteins were upregulated, while those encoding aspartyl proteases were downregulated in M. restricta after co-culturing with Staphylococcus species. We identified MRET_3770 as a major secretory aspartyl protease coding gene in M. restricta through pepstatin-A affinity chromatography followed by mass spectrometry and found that the expression of MRET_3770 was significantly repressed upon co-culturing with Staphylococcus species or by incubation in media with reduced pH. Moreover, biofilm formation by Staphylococcus aureus was inhibited in the spent medium of M. restricta, suggesting that biomolecules secreted by M. restricta such as secretory aspartyl proteases may degrade the biofilm structure. We also examined the transcriptional changes in S. aureus co-cultured with M. restricta and found co-cultured S. aureus showed increased expression of genes encoding ribosomal proteins and downregulation of those involved in riboflavin metabolism. These transcriptome data of co-cultured fungal and bacterial species demonstrate a dynamic interplay between the two co-existing genera.

• 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.

• 한국토양비료학회지
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• 제45권4호
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• pp.551-554
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• 2012

The present laboratory investigation was conducted to assess the effect of heavy metals on carbon mineralization. Soil was treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soil) of two heavy metals (Cd and Zn) in a factorial combination of treatments replicated four times. Determination of carbon mineralization was carried out at 3, 7, 14, 21, 28, 42 and 56 days after metal treatments.. The amount of $CO_2$-C released from heavy metal treated soils was found to be decreased at an increasing rate during the first 28 days, followed by slow release as incubation progressed. The total amounts of $CO_2$-C released were 448, 382 and $348mg\;kg^{-1}$ soil respectively for soils treated with 50, 100 and $150{\mu}mol\;g^{-1}$ soil of Zn. The corresponding figures for Cd treated soils were 406, 354 and $282mg\;kg^{-1}$ soil implying that dose-dependent reduction in cumulative $CO_2$-C released from soils. The inhibition of carbon mineralization was found to be high in Cd treated soils than that of Zn treated. Therefore, tolerance and adaptation of the microbial community is likely to be related to the concentration and the type of metal. According to the results, carbon mineralization can be considered as possible indicator of soil pollution by means of heavy metals.

• Biomaterials and Biomechanics in Bioengineering
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• 제3권1호
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• pp.37-46
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• 2016

To maintain activity in a coenzyme/enzyme mixture system, such as ${\beta}$-nicotinamide adenine dinucleotide (NADH)/dehydrogenase, the water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers as an additive were synthesized and investigated for their stabilizing function. The inhibitor for the NADH/dehydrogenase reaction was spontaneously formed when the NADH was stored in the dehydrogenase solution. Therefore, we hypothesized that if the additive polymer could interact with an inhibitor without any adverse effect on the dehydrogenase, the activity in the NADH/dehydrogenase mixture could be maintained. We selected lactose dehydrogenase (LDH) as the enzyme, and the NADH was dissolved and incubated at $37^{\circ}C$ in the LDH solution containing the polymers. The phospholipid polymers used in this study were poly(MPC) (PMPC), poly(MPC-co-3-trimethylammonium-2-hydroxypropyl methacrylate chloride) (PMQ) and poly[MPC-co-potassium 3-methacryloyloxypropyl sulfonate ($MSO_3$)] ($PMMSO_3$). The poly($MSO_3$) was used as a reference. For the PMQ and $PMSO_3$ aqueous solutions, the activity of the NADH/LDH mixture system decreased with incubation time as the same level or lower than that in the Tris buffered solution in the absence of the polymers. However, for the poly($MPC-co-MSO_3$) ($PMMSO_3$) aqueous solution, the activity of the NADH/LDH mixed system was six times higher than that in the buffered solution even after a 3-days incubation. The LDH activity was 1.5-1.8 times higher in the presence of the $PMMSO_3$ compared with that in the $PMSO_3$ solution. The mixture of two polymers, poly(MPC) and poly($MSO_3$), did not produce any stabilization. Thus, both the MPC and $MSO_3$ units in the polymer chain had important and cooperative effects for stabilizing the NADH/LDH mixture.

• 한국균학회지
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• 제42권3호
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• pp.247-252
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• 2014

느타리 주요 재배품종의 균사배양중 차광처리가 발이 균일도 및 생육에 미치는 영향을 조사한 결과는 다음과 같다. 배양중 수한 1호의 배지내 온도는 차광처리 시기에 관계없이 11~12일에, $24{\sim}25^{\circ}C$, 곤지 7호는 11~12일에 $25{\sim}26^{\circ}C$로 상승하였다. 온도가 가장 높게 상승되는 시점에서 수한 1호의 $CO_2$는 9~11%, 곤지 7호는 9~10% 발생되는 반면, $O_2$는 낮아지는 경향을 보여 균사생장에 좋은 조건이 이루어지고 있었다. 특히, 접종 후 배양 10일부터 차광 처리시 수한 1호는 무처리 대비 20%, 곤지 7호는 13%까지 발이 불균일이 감소하면서 발이 균일도가 가장 양호하였으며, 수량에도 차이가 없었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권6호
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• pp.461-467
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• 2005

Background. 5-(and-6)-carboxy-2',7'-dichlorofluorescein diacetate, succinimidyl ester mixed (CFSE) is the fluorescent labelling agent of living cells and used to trace the cells in vivo after transplatnation of various cells. The CFSE labelled cells can maintain fluorescence for up to 7 days after labelling. The MC3T3-E1 cell line (MC3T3) has been used for many studies about osteoblast, which is well known as a mouse preosteoblast. So the CFSE would be used to trace the transplanted MC3T3. However there are few reports about CFSE labelling of MC3T3. This study is aimed to know about adequate concenturation and incubation time of CFSE to MC3T3. Materials and methods. The MC3T3 was incubated in a humidified atmosphere of 95% air with 5% $CO_2$ at $37^{\circ}C$ using ${\alpha}$-minimal essential medium (${alpha}$-MEM) containing10% FBS and gentamycin. Ten mM CFSE solution in dimethylsulphoxide (DMSO: 1%) was diluted with phosphate buffered saline (PBS) and final concentration of culture medium was, respectively, 5, 10, 15, 20, 25 and 30 ${{\mu}M$. Then the MC3T3 was incubated with CFSE in a humidified atmosphere of 95% air with 5% $CO_2$ at $37^{\circ}C$ for 5, 10, 15, 20, 25, 30, 35, 40 and 45 minutes in each concentration. The fluorescence of CFSE labelled cells was analysed with a inverted fluorescence microscope. The duration of cell labelling was also studied. Trypan blue dye exclusion test was done for cell viability. Results. For concentration between 5 and 10 ${\mu}M$, CFSE did not significantly label the MC3T3 in vitro. The destruction of MC3T3 was observed at the concentration of 20 ${\mu}M$. In the concentration of 15 ${\mu}M$, the best labelling was obtained at an incubation period between 15 and 30 minutes. The MC3T3 labelled with an incubation period of 15 minutes at 15 ${\mu}M$ was still fluorescent 7 days after CFSE labelling. The mean cell viability was 95.93%. Conclusion. These results suggests an incubation period of 15 minutes at 15 ${\mu}M$ of CFSE provides best labelling of MC3T3 in vitro.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.845-855
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• 2015

The present study describes the gene cloning and high-level expression of an alkaline and thermostable lipase gene from Trichosporon coremiiforme V3. Nucleotide analysis revealed that this lipase gene has an open reading frame of 1,692 bp without any introns, encoding a protein of 563 amino acid residues. The lipase gene without its signal sequence was cloned into plasmid pPICZαA and overexpressed in Pichia pastoris X33. The maximum lipase activity of recombinant lipase was 5,000 U/ml, which was obtained in fed-batch cultivation after 168 h induction with methanol in a 50 L bioreactor. The purified lipase showed high temperature tolerance, and being stable at 60℃ and kept 45% enzyme activity after 1 h incubation at 70℃. The stability, effects of metal ions and other reagents were also determined. The chain length specificity of the recombinant lipase showed high activity toward triolein (C18:1) and tripalmitin (C16:0).