• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.1983-1990
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• 2007

Antidiabetic effects of a novel microbial biopolymer (PGB) 1 excreted from new Enterobacter sp. BL-2 were tested in the db/db mice. The animals were divided into normal control, rosiglitazone (0.005%, wt/wt), low PGB1 (0.1%, wt/wt), and high PGB1 (0.25%, wt/wt) groups. After 5 weeks, the blood glucose levels of high PGB1 and rosiglitazone supplemented groups were significantly lower than those of the control group. In hepatic glucose metabolic enzyme activities, the glucokinase activities of PGB1 supplemented groups were significantly higher than the control group, whereas the PEPCK activities were significantly lower. The plasma insulin and hepatic glycogen levels of the low and high PGB1 supplemented groups were significantly higher compared with the control group. Specifically, the insulin and glycogen increases were dose-responsive to PGB1 supplement. PGB1 supplement did not affect the IPGTT and IPITT compared with the control group; however, rosiglitazone significantly improved IPITT. High PGB1 and rosiglitazone supplementation preserved the appearance of islets and insulin-positive cells in immunohistochemical photographs of the pancreas compared with the control group. These results demonstrated that high PGB1 (0.25% in the diet) supplementation seemingly contributes to preventing the onset and progression of type 2 diabetes by stimulating insulin secretion and enhancing the hepatic glucose metabolic enzyme activities.

• 한국미생물·생명공학회지
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• 제44권3호
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• pp.229-235
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• 2016

우리나라는 예전부터 전통적인 방법으로 누룩을 제조하고, 이를 발효제로 막걸리를 만들어 왔다. 막걸리는 여과 또는 살균 과정없이 다양한 미생물을 살아 있는 상태로 섭취하기 때문에 영양학적으로나 기능적인 측면에서 가치가 높다. 최근 많은 연구에서 막걸리로부터 미생물을 분리동정하고 다양한 기능성에 대해 스크리닝한 결과, 높은 프로바이오틱스 활성과 다양한 스펙트럼의 항균활성을 가진 균주들이 선별되었다. 특히 일부 유산균들은 GABA와 EPS 등의 기능성 물질을 생성하기도 했다. 또한, 일부 유산균과 효모의 경우 각각 bacteriocin 및 killer toxin을 통해 항균활성을 나타내는 것으로 여겨진다. 이러한 막걸리 유래 기능성 미생물과 그 대사산물은 기능성 식품 소재나 안전한 식품첨가물 및 다양한 산업분야에서 활용될 수 있을 것이다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.37-45
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• 2015

This study was conducted to determine the toxic effect of TNT and RDX on indigenous soil microbes by measuring enzymatic activity. Denitrification activity, dehydrogenase activity, phosphatase activity, and fluorescein diacetate hydrolytic activity were determined for military firing range, field, and paddy soils exposed to TNT, and RDX from 0 to 1,000 mg/kg and 0 to 4,000 mg/kg, respectively, for 2, 4, and 8 weeks. Soil microbial enzymatic activities decreased with higher TNT and RDX concentration and longer exposure time. Microbial enzymatic activities of firing range soil were higher than field and paddy soils, indicating that indigenous microbes in firing range might have been adapted to TNT and RDX due to pre-exposure of the explosives. In addition, the toxicity of TNT and RDX decreased with higher organic matter because TNT and RDX tend to absorb to soil organic matter. No Observable Effect Concentration (NOEC) values of each microbial enzymatic activity were derived by the geometric mean of NOECs from exposure times (2, 4, and 8 weeks) and soil types (firing range, field, paddy soil). The derived NOECs ranged from 45.3 to 55.2 mg/kg for TNT and 286 to 309 mg/kg for RDX.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.155-160
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• 2005

Abstract A direct approach was used to retrieve active lipases from Paenibacillus polymyxa genome databases. Twelve putative lipase genes were tested using a typical lipase sequence rule built on the basis of a consensus sequence of a catalytic triad and oxyanion hole. Among them, six genes satisfied the sequence rule and had similarity (about 25%) with known bacterial lipases. To obtain the six lipase proteins, lipase genes were expressed in E. coli cells and lipolytic activities were measured by using tributyrin plate and pnitrophenyl caproate. One of them, contig 160-26, was expressed as a soluble and active form in E. coli cell. After purifying on Ni-NTA column, its detailed biochemical properties were characterized. It had a maximum hydrolytic activity at $30^{\circ}C$ and pH 7- 8, and was stable up to $40^{\circ}C$ and in the range of pH 5- 8. It most rapidly hydrolyzed pNPC$_6$ among various PNPesters. The other contigs were expressed more or less as soluble forms, although no lipolytic activities were detected. As they have many conserved regions with lipase 160-26 as well as other bacterial lipases throughout their equence, they are suggested as true lipase genes.

• 생약학회지
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• 제27권3호
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• pp.231-237
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• 1996

The antitumor components of the protoplast fusants of Lentinula edodes and Ganoderma lucidum were examined for immunological activity to elucidate the mechanism of their antitumor activity. They did not show any direct cytotoxicity against tumor cells. But being examined for immunopotentiation activity, they increased the number of colonies in the bone marrow stem cells to 3.0 times. They also increased the activities of the acid phosphatase in activated macrophages to 2.1 times and the secretion of nitric oxide in RAW 264.7 to 2.2 times, respectively. They activated the components of the alternative complement pathway. In humoral immunity. they increased the activities of the alkaline phosphatase in differentiated B cells to 1.6 times and the number of plaque forming cells to 1.8 times, respectively. In cellular immunity, they restored the depressed response of delayed type hypersensitivity in tumor bearing mice to normal level.

• Archives of Pharmacal Research
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• 제10권2호
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• pp.103-109
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• 1987

To find microorganisms producing esterase inhibitors, microbes were isolated from soil samples that were collected at different locations in Korea and screened for inhibitory activities. One of the inhibitor-producing strains was named strain DMC-498. This strain was found to be a new species of the genus Streptomyces by comparison with the characteristics of morphology and metabolisms of the other species of the genus.

• 한국미생물·생명공학회지
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• 제50권1호
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• pp.122-125
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• 2022

The cellulose-fed microbial fuel cell (MFC) is a biotechnological process that directly converts lignocellulosic materials to electricity without combustion. In this study, the cellulose-fed, MFC-integrated thermophilic bacterium, Bacillus sp. WK21, with endoglucanase and exoglucanase activities of 1.25 ± 0.08 U/ml and 0.95 ± 0.02 U/ml, respectively, was used to generate electricity at high temperatures. Maximal current densities of 485, 420, and 472 mA/m² were achieved when carboxymethyl cellulose, avicel cellulose, and cellulose powder, respectively, were used as substrates. Their respective maximal power was 94.09, 70.56, and 89.30 mW/m³. This study demonstrates the value of the novel use of a cellulase-producing thermophilic bacterium as a biocatalyst for electricity generation in a cellulose-fed MFC.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.54-60
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• 2001

A study was conducted to assess the nutritive value of two diets based on a low-energy variety of wheat, RAC C1 and their effects on intestinal mucosal structure and function in broiler chickens. The diets were fed with or without microbial enzyme supplement to male and female broiler chickens. The digesta viscosity was reduced (p<0.001) through supplementation with a microbial enzyme in male and female chicks. Enzyme supplementation also improved the dietary apparent metabolizable energy content (p<0.001) and had slight but non-significant positive effects on chick growth and feed conversion ratio. Intestinal mucosal structure and enzyme function were not affected by microbial enzyme supplement. Male chicks consumed more feeds (p<0.001), attained higher final body weight (p<0.001) and were more efficient at feed utilization (p<0.01) than the female chicks. Except for duodenal villus surface area and ileal protein content, intestinal mucosal structure and enzyme activities were similar between the two sexes and dietary treatment groups. The study showed an improvement in the nutritive value of the diets in the presence of the microbial enzyme supplement.

• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.303-316
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• 1994

Microbial digestion of feed in the rumen involves a sequential attack culminating in the formation of fermentation products and microbial cells that can be utilized by the host animal. Most feeds are protected by a cuticular layer which is in effect a microbial barrier that must be penetrated or circumvented for digestion to proceed. Microorganisms gain access to digestible inner plant tissues through damage to the cuticle, or via natural cell openings (e.g., stomata) and commence digestion from within the feed particles. Primary colonizing bacteria adhere to specific substrates, divide to form sister cells and the resultant microcolonies release soluble substrates which attract additional microorganisms to the digestion site. These newly attracted microorganisms associate with primary colonizers to form complex multi-species consortia. Within the consortia, microorganisms combine their metabolic activities to produce the diversity of enzymes required to digest complex substrates (e.g., cellulose, starch, protein) which comprise plant tissues. Feed characteristics that inhibit the microbial processes of penetration, colonization and consortia formation can have a profound effect on the rate and extent of feed digestion in the rumen. Strategies such as feed processing or plant breeding which are aimed at manipulating feed digestion must be based on an understanding of these basic microbial processes and their concerted roles in feed digestion in the rumen.

• Environmental Engineering Research
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• 제24권2호
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• pp.181-190
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• 2019

Constructed wetlands are improvised man-made systems, designed for adopting the principle of natural wetlands for purifying wastewater - the elixir of life. They are used widely as a cost-effective and energy-efficient solution for treating greywater generated from different tertiary treatment sources. It provides an elaborate platform for research activities in an attempt to recycle earth's natural resources. Among the several organic impurities removal mechanisms existing in constructed wetland systems, the earth's active microbial population plays a vital role. This review deals with the recent advancements in constructed wetland systems from a microbiological perspective to (effect/ devise/ formulate) chemical and physical treatment for water impurities. It focuses on microbial diversity studies in constructed wetlands, influence of wetland media on microbial diversity and wetland performance, role of specific microbes in water reuse, removal of trace elements, some heavy metals and antibiotics in constructed wetlands. The impurities removal processes in constructed wetlands is achieved by combined interactive systems such as selected plant species, nature of substrate used for microbial diversity and several biogeochemical effected reaction cycles in wetland systems. Therefore, the correlation studies that have been conducted by earlier researchers in microbial diversity in wetlands are addressed herewith.