• 한국환경과학회지
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• 제17권11호
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• pp.1221-1226
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• 2008

A variety of fungal species are known to degrade cyanide through the action of cyanide hydratase, a specialized nitrilases which hydrolyze cyanide to formamide. This work is a report on two unknown and un-characterized members from Neurospora crassa and Aspergillus nidulans. Recombinant forms of three cyanide hydratases (CHT) originated from N. crassa, Gibberella zeae, and A. nidulans were prepared after their genes were cloned with N-terminal hexahistidine purification tags, expressed in E. coli and purified using immobilized metal affinity chromatography. These enzymes were compared according to their pH activity profiles, and kinetic parameters. Although all three were similar, the N. crassa CHT has the widest pH range of activity above 50% and highest turnover rate ($6.6{\times}10^8min^{-1}$) among them. The CHT of A. nidulans has the highest Km value of the three nitrilases evaluated in here. Expression of CHT in both N. crassa and A. nidulans were induced by the presence of KCN, regardless of any presence of nitrogen sources. These data can be used to determine optimal procedures for the enzyme uses in the remediation of cyanide-containing wastes.

• 상하수도학회지
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• 제24권6호
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• pp.661-674
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• 2010

Bacterial biomass and its activity were measured in two kinds of granular activated carbon (GAC), the experimental and existing biofiltration system in a drinking water plant. The bacterial biomass was around 210 to 250 nmol P/g WW with phospholipid concentration at acclimation of ozonation treatment. The phospholipid biomass shows more or less a declining gradient along filter depth and no clear seasonality in its values. On the other hand, the microbial activity of [$^3H$]-thymidine and [$^{14}C$]-acetate incorporation within cells increased significantly along the filter depth, showing the difference of three fold between the upper and bottom layer. These factors support the different microbial composition or metabolic activity along the depth of GAC column. Turnover rates, the rate of bacterial biomass and production of biofilm, ranged from 0.26 /hr to 0.37 /hr, indicating a highly rapid recovery itself at amature state. In the non-ozonation treatment, the bacterial biomass was lower than in the ozonation and biological activity also declined towards the filter depth. The biomass levels during cessation of ozonation in the existing GAC filters were 68% of the actively ozonated state.

• BMB Reports
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• 제32권5호
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• pp.492-496
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• 1999

We have investigated the biochemical properties of the herpes simplex virus type 1 (HSV-1) DNA polymerase without the UL42 protein (Pol), purified from insect cells infected with a recombinant baculovirus containing the UL30 gene. BSA and DTT have inhibitory effects on dAMP incorporation. Pol showed a greater turnover rate of steady-state single nucleotide incorporation at 12 mM $MgCl_2$ than at 2 mM $MgCl_2$. However, it showed a greater processivity of DNA synthesis at lower $MgCl_2$ concentration (1 mM, 2 mM) than at a higher $MgCl_2$ concentration (12.5 mM). These results are consistent with a slow DNA dissociation at lower $MgCl_2$ concentrations. Pol does not incorporate a correct nucleotide into the primer with an incorrect nucleotide at the end; instead, it preferentially excises the incorrect nucleotide at the 3' end of the primer. Pol has DNA polymerase activity at pHs 6.5 and 7.5 but little at pHs 5.5, 8.5, and 9.5. It has exonuclease activity at pHs 6.5, 7.5, and 8.5 but little at pHs 4.5, 5.5, and 9.5. The finding that Pol has exonuclease activity but not DNA polymerase at pH 8.5 suggests that DNA binds to Pol, but deoxynucleotide binding or incorporation does not occur at pH 8.5.

• Journal of Nutrition and Health
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• 제31권4호
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• pp.716-728
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• 1998

To investigate the effect of dietary Ca levels on metabolic changes of Ca and skeleton in postmenopausal women, 10-month-old ovariectomized female rats were compared with 2 month old rats. The rats were fed either 0.2% or 1.2% Ca diets for 16 weeks. Food intake and weight gain as higher in rats fed high Ca diets and in ovariectomized rats. Apparent Ca absorption as higher, and Ca balance was lower in the low Ca groups. Vertebrae density was higher in old rats or those fed a high Ca diets. The old rats and ovariectomized rats showed decreased bone formation, increased bone resorption and kidney function deterioration resulting in increased urinary Ca excretion. Contradictory to the above observation, old rats and ovariectomized rats still showed higher bone mass and bone ash content. Therefore aging was not fully onging in 10-month-old rats. Bone weights, mineral contents, and mineral/wt ratio were lower in ovariectomized rats. Dietary Ca level did not affect urinary Ca excretion, urinary protein excretion, GFR, serum alkaline phosphatase, or urinary hydroxyporline excretion. This means that dietary Ca level did not influence kidney function or bone turnover. However Ca content and the ash content of femur, 4th vertebra, and scapula were increased in high Ca groups. Therefore, it is considered that decreased bone formation and accelerated bone resorption may account for the increased osteoporotic risk in women in menopause after middle age. However, Ca metabolism can be improved and bone components can be maintained if Ca is supplemented.

• 한국산학기술학회논문지
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• 제7권4호
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• pp.715-720
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• 2006

CO와 유사한 분자궤도함수를 갖는 isocyanide 리간드가 포함된$Cp(CO)_{2}(L)MH$ (L = t-butylisocyanide and 2,6-dimethylphenylisocyanide M = Mo and W)를 합성하고, 이 착물과 triflic acid를 사용하여 카르보닐기를 알코올로 전환시키는 실험을 하였다. 또한, 이들 착물을 촉매 전구체로 이용하여 3-pentanone의 수소화 반응을 온화한 조건 ($23^{\circ}C,\;<4.1\;atm H_{2}$)에서 수행하였다. 촉매 활성은 매우 낮았으며, [$Cp(CO)_{2}(ArNC)Mo][BA_{r}^{F}_{4}$]의 경우에 2 turnovers/day의 결과를 나타내었다.

• The Korean Journal of Ecology
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• 제11권2호
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• pp.55-64
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• 1988

The seasonal pattern of pool size and withdrawal from senescing or stroage organ, and the annual magintude of internal-and plant-soil cycles for nitrogen and phosphorus in a Glyceria leptolepis Ohwi population in a marsh of the Mt. Geumoh were investigared. The population pool changed from initial size of 6.8 to the maximum of 16.1gN$m^{-2}$ for N and from 1.7 to 3.9g Pm$m^{-2}$ for P, maintaining far higher relative pool size during the first half of the growth period as compared with that for biomass. A sharp increase in N and P pool was noticed in early spring before the biomass growth was recognized, The major process supplying the demand for N and P changed as the growth progressed showing the order; absorption-withdrwal-absorption-with-drawal. The annual magnitude of plant-soil cycle for N and P was 18.0-19.1 and 2.9-3.3gm$m^{-2}$, accounting for 3 and 5% of each nutrient pool in 0-20 cm humus layer, respectively. The higher exent of internal cycle and the lower rate of annual turnover for P(1.08) as compared with those for N may suggest that this population conserves and reuses P more efficiently than N.

• Asian-Australasian Journal of Animal Sciences
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• 제15권10호
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• pp.1439-1444
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• 2002

An objective of this study was to determine the effects of increasing contents of rumen undegradable protein (RUP) from formalin treated soy bean (FSBM) on rumen functions. Four rumen canulated non-lactating cows were randomly allocated to total mixed rations (TMR) containing different proportions of soy bean meal (SBM) and FSBM. Of rumen fermentation characteristics, concentrations of ruminal fluid ammonia and molar proportions of isoacids decreased with increasing contents of RUP in diets (p<0.01). The animals on TMR containing only SBM gained less weight and had smaller rumen volume than those on TMR containing RUP from FSBM (p<0.05). Organic matter and neutral detergent fiber digestibility in sacco were not different (p>0.05). The density of protozoa particularly small Entodinium sp. in ruminal fluid was higher in animal fed TMR containing SBM:FSBM (34:66) and FSBM than those fed TMR containing SBM:FSBM (66:34) and SBM (p<0.01). Total viable count, and net microbial protein synthesis as indicated by purine derivatives in urine increased with increasing contents of RUP from FSBM (p<0.01). It can be concluded that a reduction in net microbial protein synthesis in the rumen with increasing contents of RUP in the diet can be due to the reduction of preformed protein available for microbial growth as well as an increased turnover rate of microbial cells by predatory activity of protozoa.

• 한국치위생학회지
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• 제20권2호
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• pp.209-220
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• 2020

Objectives: Although dental hygienists have a high employment rate as professional workers, turnover and retirement rates are very high. This study analyzed the factors related to work life of dental hygienists to prepare an alternative for life extension. Methods: From August 1 to December 31, 2019, 224 dental hygienists and 446 dental hygiene students were examined. Results: The expected working years for dental hygienists were 10-14 years (25.4%) and over 31 years (22.4%) for dental hygiene students. The recognized working years for dental hygienists were 10-14 years (22.4%) and 20-24 years (26.0%) for dental hygiene students. Work values of dental hygienists and dental hygiene students averaged 3.85 and 3.86, respectively. Furthermore, the average motive for selecting a major in dental hygienists was 3.08 points and in dental hygiene students, 3.24 points. The average career identity of dental hygienists and dental hygiene students were 2.82 and 2.91 points, respectively. Conclusions: The perception difference between dental hygienists and dental hygiene students was compared, and the factors that could play a positive role in prolonging life were identified. Based on this study, further systematic comparative studies and preparation of alternatives for life extension are required.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1992년도 제1회 신약개발 연구발표회 초록집
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• pp.39-39
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• 1992

5-Hydroxytryptamine(serotonin, 5-HT)은 중추신경의 신경 전달물질로서 조울병, 불안신경증 등의 정신병태생리에 중요한 역할을 한다. Radioligand 결합실험에 의하여 5-$HT_{1A}$, 5-$HT_{1B}$, 5-$HT_{1C}$, 5-$HT_{1D}$, 5-$HT_{2}$, 5-$HT_3$의 5-HT receptor subtypes의 존재가 확인되어 있고, 그 중에서도 5-$HT_{1A}$ receptor는 중추작용 증 정 도의 조절에 관계가 깊은 raphe nuclei 및 해마에 주로 존재하여 약리학적으로는 체온강하, 혈압 강하, 과식작용, corticosterone 분비 등과 관련되어 있음이 알려져 있다. 따라서 본 수용체 agonist가 항불안약, 항우울약 또는 항고혈압약으로서의 응용이 가능해지면서 5-$HT_{1A}$ 수용체 기능의 해명 및 그 agonist의 개발이 주목받고 있는 가운데, 본 연구에 있어서, 항불안약 개발목적으로 합성된 일련의 화합물 중 1-<3-(3,4-methylene-dioxyphenoxy)propyl> 4-phenyl piperazine (DP-554)이 5-HT 수용체에 특이적이고 선택적으로 높은 친화성을 가지며, rat 해마의 막분획에서 adenylate cyclase 활성을 억제하고, 뇌내 5-HT turnover rate를 감소시키는 둥의 약리학적 작용을 나타내어, 이 화합물이 5-$HT_{1A}$ receptor agonist로서 작용함을 밝혔다. Mouse vas deferens (MVD)를 이용한 실험에서 5-$HT_{1A}$ receptor가 MVD의 교감신경 말단에 존재하여 그 neurotransmission을 억제함이 시사되었으며, 이 조직에서 또한 5-$HT_2$와 5-$HT_3$ 수용체의 존재를 확인하고 각각의 기능을 분명히 했다.

• 한국직업건강간호학회지
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• 제18권2호
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• pp.165-173
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• 2009

Purpose: In Korea, the number of migrant workers is increasing. However, migrant workers have low job satisfaction due to poor working environment, and insufficient social support. This study aimed to investigate the role of social support for job satisfaction of migrant workers. Method: We have analyzed the survey data of 397 migrant workers collected from free clinic for migrant workers located in Seoul, Gyeonggi-do and Chungcheong-do. Result: When the migrant workers received monetary and emotional supports from supervisors and colleagues, their job satisfaction turned out to be significantly high. The factors that influence job satisfaction of migrant workers are as follows: involvement in manufacturing industry, over 9 hours of daily sleep, monetary and emotional support from supervisors. Their job satisfaction strongly influenced by these factors. Conclusion: Social support will increase job satisfaction of migrant workers and it will subsequently decrease job turnover rate and increase productivity as well as quality of life.