• Korean Journal of Microbiology
• /
• v.48 no.3
• /
• pp.200-206
• /
• 2012

A bacterial strain capable of synthesizing polyhydroxyalkanoates (PHAs) with an unusual pattern of monomer units was isolated from activated sludge using the enrichment culture technique. The organism, identified as Pseudomonas aeruginosa P-5, produced polyesters consisting of 3-hydroxyvalerate and medium-chain-length (MCL) 3-hydroxyalkanoate monomer units when $C_{-odd}$ alkanoic acids such as nonanoic acid and heptanoic acid were fed as the sole carbon source. Solvent fractionation experiments using chloroform and hexane revealed that the 3-hydroxyalkanoate monomer units in these polyesters were copolymerized. The molar concentration of 3-hydroxyvalerate in the polyesters produced were significantly elevated up to 26 mol% by adding 1.0 g/L valeric acid as the cosubstrate. These copolyesters were sticky with low degrees of crystallinity. The PHA synthase genes were cloned, and the deduced amino acid sequences were determined. P. aeruginosa P-5 possessed genes encoding MCL-PHA synthases (PhaC1 and PhaC2) but lacked the short-chain-length PHA synthase gene, suggesting that the MCL-PHA synthases from P. aeruginosa P-5 are uniquely active for polymerizing (R)-3-hydroxyvaleryl-CoA as well as MCL (R)-3-hydroxyacyl-CoAs.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.4
• /
• pp.5-9
• /
• 2016

In the modern industrial society, huge amount of organic wastes have exceeded the society's self-cleaning capability, caused pollution of the whole environment, including water quality, soil, and the air, and become a big burden of waste treatment. Moreover, the emission of green house gases brought by the continual combustion of fossil fuels has facilitated the global warming. The simultaneous effect of initial and operational pH on $H_2$ yield was expressed using mathematical equation and optimized. The optimal initial and cultivation pH was 7.50 and 6.01, respectively. Addition of livestock wastewater to food waste substantially decreased the amount of alkali requirement and also improved the $H_2$ fermentation performance.

• Korean Journal of Microbiology
• /
• v.41 no.3
• /
• pp.225-231
• /
• 2005

The characteristics of cell growth and medium-chain-length polyhydroxyalkanoate (MCL-PHA) biosynthesis of Pseudomonas chlororaphis HS21 were investigated using plant oils as the carbon substrate. The organism was efficiently capable of utilizing plant oils, such as palm oil, corn oil, and sunflower oil, as the sole carbon source for growth and MCL-PHA production. When palm oil (5 g/L) was used as the carbon source, the cell growth and MCL-PHA accumulation of this organism occurred simultaneously, and a high dry cell weight (2.4 g/L) and MCL-PHA ($40.2\;mol{\%}$ of dry cell weight) was achieved after 30 hr of batch-fermentation. The repeating unit in the MCL-PHA produced from palm oil composed of 3-hydroxyhexanoate ($7.0\;mol{\%}$), 3-hydroxyoctanoate ($45.3\;mol{\%}$), 3-hydroxydecanoate ($39.0\;mol{\%}$), 3-hydroxydodecanoate ($6.8\;mol{\%}$), and 3-hydroxytetradecanoate ($1.9\;mol{\%}$), as determined by GC/MS. Even though glucose was a carbon substrate that support cell growth but not PHA production, the conversion rate of palm oil to PHA was significantly increased when glucose was fed as a cosubstrate, suggesting that bioconversion of some functionalized carbon substrates to related polymers in P chlororaphis HS21 could be enhanced by the co-feed of good carbon substrates for cell growth. In addition, the change of compositions of repeating units in MCL-PHAs synthesized from the plant oils was markedly affected by the supplementation of acrylic acid, an inhibitor of fatty acid ${\beta}-oxidation$. The addition of acrylic acid resulted in the increase of longer chain-length repeating units, such as 3-hydroxydodecanoate and 3-hydroxytetradecanoate, in the MCL-PHAs produced. Particularly, MCI-PHAs containing high amounts of unsaturated repeating units could be produced when sunflower oil and corn oil were used as the carbon substrate. These results suggested that the alteration of PHA synthesis pathway by acrylic acid addition can offer the opportunity to design new functional MCL-PHAs and other unusual polyesters that have unique physico-chemical properties.

• Development and Reproduction
• /
• v.12 no.1
• /
• pp.41-49
• /
• 2008

Ultrastructural changes occurring during the course of development and degeneration of oocytes in female Ruditapes philippinarum (Adams & Reeve, 1850) are described for clams collected from Gomso Bay, Korea. During the early stages of oogenesis, desomosome-like gap junctions localized between the early vitellogenic oocyte and the follicle cells. Vitellogenesis occurs through a process of autosynthesis, involving the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum, and heterosynthesis in which extraovarian precursors are incorporated into oocytes by endocytotic activity, involving the basal region of the early vitellogenic oocytes prior to the formation of the vitelline envelope. The follicle cells appear to play an integral role in vitellogenesis and oocyte degeneration: phagocytosis and intracellular digestion of products originating from oocyte degeneration. These functions can permit a transfer of yolk precursors necessary to vitellogenesis, and they can accumulate nutrients in the cytoplasm, as glycogen and lipids, which can be employed by the vitellogenic oocyte. During the period of oocyte degeneration, follicle cells may have lysosomal system for breakdown, and resorb various phagosomes in the cytoplasm for nutrient storage. But follicle cells probably are not the major source of yolk precursors in vitellogenesis.

• Proceedings of the Korean Nutrition Society Conference
• /
• 2004.05a
• /
• pp.122-122
• /
• 2004

골관절염은 관절연골의 퇴행성 변화로 연골기질의 분해로 인하여 연골 강도와 cushion으로서의 능력이 감소되는 질환이다. 골관절염의 대부분 약물치료는 통증과 염증을 감소시키는 목적으로 사용되며, 근본적인 치료효과를 주는 약물은 현재까지 개발되어 있지 않다. 영양약학 제품에 대한 질병의 예방적, 치료 보조적 차원에서 인체에 대한 기초적인 생리활성의 중요성을 인식하게 됨으로써 그 역할이 중요하게 인식되고 있다. 특히, 골관절염 치료에 쓰이는 glucosamine은 proteoglycan (PG)와 glucosaminoglycans(GAGs)의 합성의 전구물질로서 연골세포 생성을 자극하며, 통증, 염증의 경감 및 진행과정을 억제시키고, 관절기능 회복을 촉진하는 것으로 알려져 있다. 그러나 glucosamine이 어떤 기전에 의해 관절연골세포에 직접적인 영향을 주는지 밝혀져 있지 않다. 본 연구에서는 glucosamine sulfate가 연골세포에 미치는 영향을 규명하고자 하였다.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.1
• /
• pp.117-124
• /
• 2020

In this paper, we proposed a plan to maintain comfortable indoor air quality in nursing homes by suggesting ways to reduce items temporarily exceeding the reference values through real-time concentration variation analysis of indoor air quality. Five items including PM10, CO₂, CO, VOC, and Radon are measured at nursing homes in spring (April) and autumn (September) was carried out and all of the measured items were analyzed to satisfy the criteria set by the Indoor Air Quality Control Act. As a result of the analysis of the real-time concentration change, the concentration of CO₂ was close to the reference value based on the number of occupants in the sick room. Due to the disinfectant (alcohol) used to disinfect and the auxiliary tools (adhesive) used in the operation of the program such as making and coloring, it was analyzed to temporarily exceed the standard value in the hall. In conclusion, it is possible to provide pleasant indoor air quality and contribute to securing the nursing home's competitiveness if periodic ventilation, natural disinfectant and eco-friendly product are used in consideration of the thermal environment.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
• /
• v.55 no.6
• /
• pp.527-537
• /
• 2018

Column tests of a sulfate reducing bacteria (SRB) bioreactor were conducted to determine the design factors for sulfate-rich mine drainage. Various substrates were applied to the bioreactor, including cow manure and its mixture with a mushroom compost, with rice straw and limestone as subsidiary materials. This procedure provided a removal efficiency of up to 82% of the total sulfur with the mixture of cow manure (70%), mushroom compost (10%) and rice straw (20%), and higher efficiencies were observed after 2 days of retention time. In the downflow condition of the flow direction, oxygen supply and re-oxidation of the sulfates occurred, causing a decrease in sulfate removal efficiency. The addition of an inorganic sludge containing heavy metals, which was intended for production of metal-sulfides in the bioreactor, had a negative effect on the long-term operation owing to arsenic release and toxicity to the SRB. The results thus show that a bioreactor using a mixed substrate with cow manure and operating in the downflow direction could reduce sulfates and total dissolved sulfur content; this process confirms the applicability of the SRB bioreactor to sulfate-rich saline drainage.

• Korean Journal of Psychosomatic Medicine
• /
• v.15 no.1
• /
• pp.7-13
• /
• 2007

Antidepressants are used by substantial number of physicians as well as psychiatrists. Antidepressants are the mainstay of treatment of depression combined with physical illness, neuropathic pain, and various psychosomatic disorders. Antidepressants, especially TCA and SSRI, are superior to placebo in treating comorbid depression and pain of physical illness. Although it has been controversial whether the influence of depression on the risk and outcome of physical illness is true, antidepressants would provide more favorable prognosis and better quality of life for the patients with physical illness.

• Journal of Life Science
• /
• v.33 no.5
• /
• pp.436-444
• /
• 2023

Scientific training, diet, and ergogenic aids are widely used to overcome the limits of humans' physical abilities and to achieve excellent sports records. The adoption of nutritional strategies is important for athletes to perform at their highest level, and one of the main factors determining endurance ability is increased fat metabolism. A ketogenic diet (high fat, low carbohydrates) has thus been proposed as an alternative strategy to maximize fatty acid oxidation during prolonged periods of exercise. However, studies have shown mixed results regarding the ergogenic value of a ketogenic diet. For this reason, exogenous ketone supplements (EKS, ingestible forms of ketone bodies, ketone esters, and/or salts) have been suggested to obtain nutritional ketosis, an acute transient increase in circulating acetoacetate (AcAc) and b-hydroxybutyrate (bHB) concentrations, without limiting carbohydrate intake. Some studies have suggested the beneficial effects of EKS on the performance of endurance exercises by providing an additional fuel substrate for peripheral tissues, such as cardiac and skeletal muscles, sparing carbohydrates/increasing fat oxidation and post-exercise recovery by increasing glycogen resynthesis in the liver/muscle, attenuating protein degradation, stimulating protein synthesis in the skeletal muscle, etc. However, many studies have failed to observe the beneficial effects of EKS as an ergogenic aid. As such, this review summarizes the theoretical basis of, as well as the proposed and proven effects of EKS on exercise performance and recovery to date.

• Clinical and Experimental Pediatrics
• /
• v.52 no.5
• /
• pp.576-580
• /
• 2009

Purpose : Growth-promoting attempts are widespread in Korea, but little is known about their prevalence or associated factors. This study was designed to assess the prevalence of growth-promoting attempts among children visiting a university growth clinic. Methods : A questionnaire-based survey was carried out with 823 children (416 boys, 407 girls) who visited the growth clinic at Paik Hospital. Results : The mean age of the subjects was $10.4{\pm}2.6$ yr, and the height z-score was $-1.58{\pm}0.91$. Approximately 33.4% of the children had tried growth promotion. Among the height-gain methods, herbal medicine was the most frequently used (37.8%), followed by health-promoting supplements (37.1%), exercise or machine (3.0%), and growth hormone treatment (2.9 %). The mean age at which the parents began to worry about their children's height was 7.7 yr. The mean age at which they started height-gain methods was 8.9 yr for herbal medicine, 9.1 yr for health-promoting supplements, 9.4 yr for exercise or machine, and 9.9 yr for growth hormone treatment. Motivating factors included advice from relatives or friends (36.0%), advertisements in the Internet or newspaper (28.4%), advice from pharmacist (16.8%), and advice from their medical doctor (5.5%). The degree of satisfaction from the height-gain methods was 29.1% with growth hormone treatment, 6.6% with exercise or machine, 6.4% with herbal medicine, and 2.8% with growth-promoting supplements. Conclusion : Approximately one third of the children reported use of growth-promoting methods, but the satisfaction rate was not high. The benefits of growth-promoting methods should be carefully weighed against their costs and side effects.