• 한국미생물·생명공학회지
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• 제39권3호
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• pp.218-223
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• 2011

Eicosapentaenoic acid 생산 세균을 얻기 위해 1999~2000년 하계연구 기간 중에 남극 생물 및 침적토를 사용하여 600주의 균주를 분리하였고 TLC와 GC를 사용하여 오메가-3 고도불포화 지방산 EPA를 생산하는 미생물 7 주를 성공적으로 분리하였으며, 이중 EPA 생산이 가장 높은 L93 균주를 선발하였다. 16S rDNA의 염기서열 분석을 통하여 Shewanella 속으로 조사되었으며, 이에 분리된 균주를 Shewanella sp. L93라 명명하였다. EPA를 생산 최적 배양온도 $4^{\circ}C$이며, 초기 pH 7에서 최적 EPA 함량을 보였다. 아울러 염 농도는 50 %(w/v)에서 생산이 최대였다. EPA 최적 생산 조건을 이용하여 리터당 320 mg 생산할 수 있는 생산 시스템을 확립하였다. Urea 침전법과 HPLC을 이용하여 수율 72% 이상의 97% 순도를 가진 EPA를 정제할 수 있는 분리 정제 시스템 또한 본 연구를 통하여 확립하였다.

• 한국어류학회지
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• 제18권1호
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• pp.20-26
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• 2006

동자개(Pseudobagrus fulvidraco), 대농갱이(Leiocassis ussuriensis) 및 이들간 잡종의 염색체수는 모두 2n=52로 동일하였으나, 핵형은 서로 상이하여 동자개가 22 metacentrics (M)+22 submetacentric (SM)+8 acrocentric (A) chromosome으로, 대농갱이는 22M+14SM+16A, 그리고 잡종은 22M+18SM+12A로 구성되어 있었다. 잡종은 동자개, 대농갱이 각각의 반수체로 구성되어 있었다. 적혈구 세포 및 핵의 크기, 표면적 및 체적을 측정한 결과 유도된 잡종은 양친의 중간값을 나타내었다. 동자개, 대농갱이 및 잡종의 DNA 함량을 측정한 결과, 동자개는 2.06 pg/cell, 대농갱이는 2.09 pg/cell, 동자개와 대농갱이 잡종은 2.08 pg/cell로 나타나, 잡종의 DNA 함량은 양친의 중간값으로 나타났다.

• KSBB Journal
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• 제26권6호
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• pp.552-556
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• 2011

A novel agar-degrading bacterium mbrc-1 was isolated from seashore of Kyungpo at Gangwon province and cultured in marine broth 2216 medium. Isolated bacterium mbrc-1 was named as Flammeovirga sp. mbrc-1 based on the 16S rDNA sequence. Its agarase showed maximum activity of 923 units/L at pH 7.0 and $45^{\circ}C$ and sustained 90% remaining activity after exposed to $45^{\circ}C$ for 2 hours. The enzyme hydrolyzed agarose to yield neoagarohexaose (18.5%), neoagarotetraose (38%) and neoagarobiose (43.5%), indicating that the enzyme is ${\beta}$-agarase. Thus, isolated bacterium and its ${\beta}$-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose.

• 한국환경과학회지
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• 제19권4호
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• pp.389-397
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• 2010

The in vitro toxicities of three crude oils of the Hebei Spirit were examined on laboratory grown plankton, with a focus on the effects of a dispersant. The specific growth rate of phytoplankton and the mortalities of two zooplankton were measured in response to exposure to various concentrations of water accommodated oil, dispersant or both. The effects of the oils varied among the plankton, but were generally low within the range of the oil concentrations used, with little difference in toxicity among the three oils. Such low toxicity appeared to be associated with weathering of the crude oils. Exposure to the dispersant, however, dramatically increased the mortality of zooplankton, with complete inhibition of phytoplankton growth. No synergistic toxic effect was observed with the crude oil and dispersant combination. A better decision making process could be crafted for future application of dispersant in the event of an oil spill in Korean waters to better protect the marine plankton community from the excessive use of dispersant.

• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1621-1629
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• 2008

Harmful algal blooms (HABs), commonly called red tides, are caused by some toxic phytoplanktons, and have made massive economic losses as well as marine environmental disturbances. As an effective and environment-friendly strategy to control HAB outbreaks, biological methods using marine bacteria capable of killing the harmful algae or algicidal extracellular compounds from them have been given attention. A new member of the $\gamma$-Proteobacteria, Hahella chejuensis KCTC 2396, was originally isolated from the Korean seashore for its ability to secrete industrially useful polysaccharides, and was characterized to produce a red pigment. This pigment later was identified as an alkaloid compound, prodigiosin. During the past several decades, prodigiosin has been extensively studied for its medical potential as immunosuppressants and antitumor agents, owing to its antibiotic and cytotoxic activities. The lytic activity of this marvelous molecule against Cochlodinium polykrikoides cells at very low concentrations ($\sim$l ppb) was serendipitously detected, making H. chejuensis a strong candidate among the biological agents for HAB control. This review provides a brief overview of algicidal marine bacteria and their products, and describes in detail the algicidal characteristics, biosynthetic process, and genetic regulation of prodigiosin as a model among the compounds active against red-tide organisms from the biochemical and genetic viewpoints.

• Ocean and Polar Research
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• 제39권4호
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• pp.269-277
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• 2017

Medium compositions for the hyperthermophilic archaeon, Thermococcus onnurineus NA1 was statistically optimized to enhance formate-driven hydrogen ($H_2$) production by using response surface methodology. From the Plackett-Burman design-based experiment, it was confirmed that among the minor components of medium such as KCl, $MgSO_4$, $NH_4Cl$, Cystein-HCl, trace elements, Fe-EDTA and $CaCl_2$, the trace elements were screened as the only positively effective components with respect to $H_2$ production. Subsequently, the optimal concentrations of the trace elements and the major components of a medium such as NaCl, yeast extract and sodium formate were determined from the five-level central composite design (CCD)-based experiment. The resulting quadratic model predicted the maximum $H_2$ production of 46.6 mmol/L in serum bottle and it was validated experimentally using the optimal medium initially supplemented with 26.70 g/L of NaCl, 9.81 g/L of sodium formate, 3.50 g/L of yeast extract and 4.59 mL/L of trace elements. From the duplicate batch cultivations in the fermentor using the optimized medium, the a maximum $H_2$ production rate up to 71.8 mmol/L/h could be obtained, which was a 65% enhanced value compared with that obtained using the control medium, showing the high efficiency of the optimized medium.

• 한국미생물·생명공학회지
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• 제34권1호
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• pp.1-6
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• 2006

Harmful algal blooms (HABs or red tides), caused by uncontrolled proliferation of marine phytoplankton, impose a severe environmental problem and occasionally threaten even public health. We sequenced the genome of an EPS-producing marine bacterium Hahella chejuensis that produces a red pigment with the lytic activity against red-tide dinoflagellates at parts per billion level. H. chejuensis is the first sequenced species among algicidal bacteria as well as in the order Oceanospirillales. Sequence analysis indicated a distant relationship to the Pseudomonas group. Its 7.2-megabase genome encodes basic metabolic functions and a large number of proteins involved in regulation or transport. One of the prominent features of the H. chejuensis genome is a multitude of genes of functional equivalence or of possible foreign origin. A significant proportion (${\sim}23%$) of the genome appears to be of foreign origin, i.e. genomic islands, which encode genes for biosynthesis of exopolysaccharides, toxins, polyketides or non-ribosomal peptides, iron utilization, motility, type III protein secretion and pigment production. Molecular structure of the algicidal pigment was determined to be prodigiosin by LC-ESI-MS/MS and NMR analyses. The genomics-based research on H. chejuensis opens a new possibility for controlling algal blooms by exploiting biotic interactions in the natural environment and provides a model in marine bioprospecting through genome research.

• 한국수산과학회지
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• 제50권4호
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• pp.372-377
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• 2017

A feeding trial was conducted to evaluate the effects of partial replacement of fishmeal (FM) protein in a practical diet for rockfish Sebastes schlegeli juveniles with mealworm Tenebrio molitor meal (WM), in terms of growth performance, feed utilization, whole body composition and hematological parameters. Four isonitrogenous and isoenergetic diets were formulated to contain 8, 16, 24 and 32% WM (designated as WM8, WM16, WM24 and WM32). A FM-based diet without WM inclusion was used as a control. Triplicate groups of rockfish ($2.6{\pm}0.07g$) were hand fed one of the experimental diets to visual satiation twice a day for 8 weeks. Weight gain of fish fed the WM32 diet was lower than that of control. No significant differences were found in daily feed intake, feed efficiency and protein efficiency ratio. The whole-body protein content of fish fed WM0 and WM8 diets were significantly higher than that of fish fed WM32 diet. No statistical differences were observed in hematological parameters. These results indicate that WM has potential as alternative to FM in practical diets for juvenile rockfish and can be used at an inclusion level of up to 24% without having a significant negative effects on growth and feed efficiency.

• 한국해양바이오학회지
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• 제2권2호
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• pp.113-119
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• 2007

본 실험은 홍조 해조류의 하나인 우뭇가사리를 추출, 각 용매별로 분획하여 항균효과와 암세포 성장억제 및 QR 유도활성 효과 등의 생리활성을 연구하였다. 우뭇가사리의 각 분획물 GAMM, GAMH, GAMB 및 GAMA층을 단백질 식품 부패 원인균인 Serratia marcescens, Proteus mirabilis의 2종과 감염형 세균성 식중독 원인균인 Salmonella enteritidis, 부패균인 Bacillus subtilis, 식중독 원인균인 Starpylococcus aureus 등 총 5 가지 균종에 처리하여 항균력을 조사한 결과 GAMM층에서 높은 가장 높은 항균 활성 효과를 나타내었다. 또 4종의 인체 암세포주 HT-29, HepG2, MCF-7 및 B16F-10 세포주에 대한 암세포 증식 억제 실험을 한 결과 사용한 4종의 모든 암세포주에서 methanol 분획층인 GAMM에서 낮은 농도의 시료첨가에도 불구하고 괄목할 만한 높은 암세포 성장 억제효과를 나타내었다. 한편, 사용한 4가지 암세포주중 유일하게 quinone reductase를 가지고 있는 HepG2를 이용한 암예 방지표인 quinone reductase 효소 유도 활성 여부를 측정한 결과 분획물 첨가농도를 10, 20, 30 및 $40{\mu}g/mL$로 첨가하였을 때 GAMM의 첨가농도 $20{\mu}g/mL$에서 대조군에 비해 약 2배 이상의 높은 QR유도효과를 나타내었고 최종농도 $40{\mu}g/mL$에서는 2.5배의 암예방 QR 유도효과를 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.520-522
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• 2008

A new compound named soraphinol C (1) was isolated from myxobacteria Sorangium cellulosum KM1001 a soil isolate, together with a structurally related known compound, 4-hydroxysattabacin (2). These compounds were isolated by silica gel column chromatography and recycling preparative HPLC, consecutively. The structures of the compounds were determined on the basis of combined spectroscopic analyses. Compounds 1 and 2 exhibited antioxidant activity as a radical scavenger in the experiment using a hydrophilic free-radical initiator, 2,2'-azobis(2-amidinopropane)dihydrochloride with ORAC values of 0.956 and 0.617, respectively.