펩타이드형 독소인 마이크로시스틴(microcystins, MCs) 과 노둘라린(nodularin, NOD)은 남조류라고도 알려진 시 아노박테리아에 의해 생성되는 2차 대사산물로, 독소에 오 염된 물, 토양 및 비료를 사용함으로써 농산물 내에 축적 되고 이를 사람이 섭취함으로써 건강상 위해가 발생할 수 있다. 최근 MCs과 NOD의 농산물 내 오염에 대한 관심 이 대두되며 국내외에서 여러 분석법을 기반으로 농산물 내 오염 수준을 조사하고 있다. 하지만 아직까지 수행된 연구가 많지 않으며, 특히 펩타이드형 독소 중 MCs의 분 석 연구에 치중되어 있거나 오염 취약 지역에서 재배한 농산물이 주로 오염도 조사에 사용되는 등 연구에 한계가 있으므로 MCs과 NOD의 관리를 위해서는 보다 많은 체 계적인 연구가 필요할 것으로 생각된다. 본 연구에서는 체 계적인 모니터링 및 안전관리의 기반을 마련하기 위해 MCs 및 NOD의 이화학적 특성, 독성, 분석법, 오염사례 및 관리현황에 대해 기술하였다.

자생식물은 관상용, 약용, 식량자원으로 활용될 수 있는 잠재력을 지닌 고유 유전자원이다. 돌부추(Allium koreanum H.J. Choi & B.U. Oh)는 우리나라 해안 암반지대에 분포하는 자생식물 중 하나로, 기후변화와 서식지 감 소로 인해 보전 가치가 높은 식물이다. 이번 연구는 온도와 과산화수소가 돌부추의 발아에 미치는 영향을 조사하기 위해 수행되었다. 종자를 무처리(대조군) 또는 1% 과산화수소(H2O2)로 90분간 처리한 종자를 준비해 15, 20, 25°C 로 설정된 식물 생장 챔버에 배치하였다. 그 결과, 파종 23일 후 15°C에서 42%인 발아율이 20°C와 25°C에서 각각 18%와 0%인 발아율보다 2배 이상 높았으며, H2O2 처리 여부와 관계없이 15°C에서 발아율이 42%로 가장 높았다. H2O2 처리와 관계없이 최종 발아율 50%(T50)에 도달하는 일수는 20°C에서 가장 짧았지만, 일평균 발아율(MDG)은 15°C에서 가장 높았다. 따라서 1%의 H2O2 처리는 돌부추의 발아율에 큰 영향을 미치지 않았으며, 15°C의 온도가 돌부추의 발아율을 높이는 데 최적인 것으로 판단된다. 본 연구 결과는 돌부추의 발아를 위한 기초 연구 자료로 활 용될 수 있을 것으로 기대된다.

본 연구는 패류 독소 중 기억상실성 독성을 유발하는 domoic acid의 분석법 개선, 검증 및 분석적용성을 살펴보 았다. SAX 카트리지 정제, 검체 및 추출용매 양의 변경 과 더불어 이동상을 용매구매 조건으로 변경시킨 분석법 은 지중해담치, 홍게 그리고 멸치의 세 가지 매트릭스를 대상으로 세 농도에 대하여 식품공전법과 비교하여 유효 성을 검증하였다. 그 결과 변경된 분석법은 LOD 0.02-0.03 mg/kg, LOQ 0.05-0.09 mg/kg, 일내 및 일간 정확도 86.2- 100.4%와 일내 및 일간 정밀도 0.2-4.0%로 CODEX가이 드라인을 만족하는 우수한 분석능을 나타내었다. 특히 변 경된 시험법에서는 domoic acid와 유사한 머무름 시간을 갖는 방해물질이 검출되지 않아 위양성 결과를 방지할 수 있을 것으로 생각된다. 더 나아가 본 분석법이 국내 유통 중인 수산물을 대상으로 적용될 수 있는지 확인하고자 식 품공전의 기억상실성 패독 분석법과 함께 수산물에 적용 하여 분석하였다. 그 결과 5종의 수산물 87건 중 공전시 험법으로 분석했을 때 domoic acid가 검출된 시료는 없었 으나 변경된 분석법을 통하여 멸치 1건에 대하여 0.14 mg/ kg의 domoic acid이 미량 검출되었다. 따라서 본 연구에 서 확립된 분석법은 수산물 중 domoic acid 분석에 활용 이 가능할 것으로 보인다.

This qualitative case study explores multilingual learners’ linguistic practices and how they are interrelated with their identities in the context of a Korean alternative school. The learners are two Chosunjok, and one North Korean refugee child. The data were derived from the learners’ digital storytelling videos, semi-structured interviews, stimulated-recall interviews, and observation field notes. The data were thematically analyzed and organized using Rose’s (2007) sites of visual meaning-making structure. The findings revealed that the learners had different amounts of access to information regarding second language learning, and that they depended on the resources available within the communities they belonged to. Moreover, the participants’ levels of investment in language learning were constructed around their communities and identities. Their attitudes in language learning were also interrelated with the broader English language ideologies in South Korea. By sharing the stories of three multilingual learners, the study provides pedagogical implications on the influence of resources on multilingual learners’ language learning. We emphasize the importance of providing a space for multilingual learners to critically reflect on current and future resources, utilize their full communicative repertoire, and identify ways to increase their affordances of learning.

For the final disposal of radioactive waste, concentration of gamma nuclides such as Co-58, Co-60, Cs-137, Nb-94 have to be determined to meet nuclear regulatory requirements. In general, gamma nuclide analysis can be performed with simple sample pretreatment without complicated chemical separation processes due to the characteristics of the nuclide and high resolution of the measuring equipment. However, when the concentration of Co-60 is high in a specific radioactive waste generated at the NPP, the background is increased by the compton continuum of Co-60. That makes it difficult to evaluate accurately Nb-94, which is in the lower energy band than the gamma ray energy region of Co-60 and especially Cs-137, which is used as a key nuclide of scaling factor. In this study, We consider the problem of MDA dissatisfaction or overestimation due to the increased background by Co-60.

Many radionuclides emit two or more gamma rays in a cascade once they decay. At this time, gamma rays are detected at the same time, and the signals are overlapped and measured as one added signal. This is called the summing coincidence effect, and it causes an error of more than 10% depending on the detection efficiency, measurement conditions, and target nuclide. It is known to be greater as the efficiency of the detector increases and as the distance between the source and the detector decreases. It is necessary to consider the summing coincidence effect since the efficiency of the HPGe detector owned by the KHNP CRI is as high as 65%. In this study, We would like to propose an appropriate gamma nuclide analysis method for radioactive waste generated from NPP by evaluating the influence on the summing coincidence effect.

In vivo oocytes grow and mature in ovarian follicles whereas oocytes are matured in vitro in plastic culture dishes with a hard surface. In vivo oocytes show a superior developmental ability to in vitro counterparts, indicating suboptimal environments of in vitro culture. This study aimed to evaluate the influence of an agarose matrix as a culture substrate during in vitro maturation (IVM) on the development of pig oocytes derived from small antral follicles (SAFs). Cumulusoocyte complexes (COCs) retrieved from SAFs were grown in a plastic culture dish without an agarose matrix and then cultured for maturation in a plastic dish coated without (control) or with a 1% or 2% (w/v) agarose hydrogel. Then, the effect of the soft agarose matrix on oocyte maturation and embryonic development was assessed by analyzing intra-oocyte contents of glutathione (GSH) and reactive oxygen species (ROS), expression of VEGFA, HIF1A , and PFKP genes, and blastocyst formation after parthenogenesis. IVM of pig COCs on a 1% (w/v) agarose matrix showed a significantly higher blastocyst formation, intra-oocyte GSH contents, and transcript abundance of VEGFA. Moreover, a significantly lower intra-oocyte ROS content was detected in oocytes matured on the 1% and 2% (w/v) agarose matrices than in control. Our results demonstrated that IVM of SAFs-derived pig oocytes on a soft agarose matrix enhanced developmental ability by improving the cytoplasmic maturation of oocytes through redox balancing and regulation of gene expression.

본 연구는 5월 일중 수확시기, 예냉 유·무, 예냉 및 저장 온도가 수출 딸기 ‘매향’의 상품성에 미치는 영향을 알아보고자 수행하였다. 과피의 착색이 60±5%로 진행된 딸기를 오전 07:00시와 오후 15:00시에 각각 수확하였다. 수확 수 일부 딸기는 예냉고에서 품온을 0, 2, 4°C로 각각 3시간 동안 예냉처리하였으며, 일부는 상온에 보관하였다. 이후 딸기는 처리별로 저장온도 4, 8, 10°C로 설정된 저온저장고에 저온 저장하였다. 저장고에 14일간 저장하면서 딸기의 무게 손실률, 경도, 당도, 색도, 잿빛곰팡이 발생률을 이틀 간격으로 조사하였다. 오전 07:00시와 오후 15:00시 수확 모두 저장기간이 경과함에 따라 수확 시 무게에 비해 무게 손실률이 증가하였으며, 오전 07:00시 수확에 비해 오후 15:00시 수확에서 처리에 따른 무게 손실률 차이가 컸다. 경도는 오전 07:00시와 오후 15:00시 수확 각각 6일째와 8일째까지 감소하다가 다시 증가하는 경향을 보였다. 오후 15:00시 수확 시 예냉하지 않은 10°C 저장 처리는 저장 후 2일째에 과실의 경도가 유의적으로 가장 낮게 나타났다. 당도는 오전 07:00시와 오후 15:00시 수확에서 예냉처리하고 낮은 저장온도 처리에서 저장일수 경과함에 따라 높은 수치로 유지되는 경향을 보였다. 색도는 일중 수확시기 및 예냉 유·무에 관계없이 낮은 저장온도에서 명도를 나타내는 ‘L’ 값은 유의적으로 높았고 적색도를 나타내는 ‘a’ 값은 유의적으로 낮은 경향을 보였다. 잿빛곰팡이 발생률은 오전 07:00시 수확에 비해 오후 15:00시 수확 시 발생률이 높았으며, 공통적으로 예냉을 한 후 10°C에 저장한 처리에서 잿빛곰팡이 발생률이 현저히 높았다. 본 연구에서 07:00시에 수확하여 0°C 예냉 후 4°C에 저장하는 것이 가장 우수한 저장성을 유지하였다. 그러므로 온도가 낮은 오전에 수확을 하고 낮은 온도에 예냉과 저장을 하는 것이 바람직하다고 판단된다.

Generally, in vivo, primary oocytes are grown and matured into secondary oocytes in the ovarian follicles. Quality of the oocytes matured in vivo is higher than that of oocytes matured in vitro, indicating the importance of materializing the microenvironment of ovarian follicles for production of high quality oocyte. Therefore, we tried to mimic the stiffness of ovarian follicles using an agarose as a biocompatible natural polymer. Unfortunately, to date, there are no many reports on whether the quality of porcine oocytes can be increased effectively under the soft matrix. Accordingly, we tried to evaluate the effects of IVM using different mechanical properties of agarose substrate on developmental competence of porcine oocytes. Agarose substrate was constructed and cumulus-oocyte-complexes (COCs) retrieved from porcine medium antral follicles were matured on non-coated (control) culture dish or dishes coated with 1% and 2% (w/v) agarose substrate. Then, cumulus expansion, embryonic development after parthenogenetic activation, and gene expression level were analyzed and compared. As the results, significant increase in blastocyst formation and cumulus expansion were detected in COCs matured on 1% (w/v) agarose substrate compared with control. Moreover, oocytes of COCs matured on 1% (w/v) agarose substrate showed significantly higher BMP15 expression level compared with control. Pro-apoptotic gene BAX expression was significantly increased in oocytes of COCs matured on 2% (w/v) agarose substrate compared with control. In the glycolytic enzyme phosphofructokinase (PFKP) gene expression, cumulus cells of COCs matured on agarose substrate showed significantly higher PFKP expression than control while they showed significantly lower BAX expression than control. These results demonstrated that quality of porcine oocytes could be increased efficiently by the IVM of immature oocytes on the soft culture matrix using agarose.

This study was conducted to evaluate the effects of insulin and epidermal growth factor (EGF) in a in vitro growth (IVG) medium on oocyte growth, in vitro maturation (IVM) and embryonic development of pig oocytes derived from small antral follicles (SAF) less than 3 mm in diameter. SAF oocytes were cultured for 2 days to induce IVG in alpha-minimal essential medium supplemented with 1 mM dbcAMP and 15% (v/v) fetal bovine serum. After IVG culture, oocyte maturation was induced by culturing IVG oocytes in IVM medium for 44 h. IVM oocytes that extruded the first polar body were selected and induced for parthenogenesis (PA) by applying electric stimulus. SAF oocytes cultured under the insulin treatment showed a significantly increased (P < 0.05) nuclear maturation (73.8%) compared to those cultured with insulin and EGF (59.8%). After PA, the proportions of blastocysts based on the number of metaphase II oocytes were significantly higher (P < 0.05) in oocytes that were cultured for IVG with insulin, EGF, and insulin + EGF (32.4%, 35.2%, and 34.8%, respectively) than in control (22.9%). IVG oocytes treated with insulin showed an increased oocyte diameter (116.3 μm) compared to those treated with insulin and EGF (114.0 μm) (P < 0.05). Intra-oocyte GSH content significantly increased (1.07 pixels/oocyte) by insulin treatment during IVG compared to that of oocytes treated with insulin + EGF (0.78 pixels/oocyte). These results demonstrate that IVG culture of SAF oocytes under insulin or/and EGF treatment supports oocyte maturation and improves embryonic development to the blastocyst stage after PA in pigs.

U0126 is a highly selective inhibitor of both MEK1 and MEK2, a type of MAPK/ERK kinase. This study was conducted to evaluate the effect of U0126 treatment during in vitro maturation (IVM) on nuclear maturation, intra-oocyte glutathione content, and embryonic development after parthenogenesis (PA). U0126 (5 μM) was supplemented to IVM medium during the first 0 (control), 2, and 4 h. The basic medium used for IVM was medium-199 supplemented with 10% (v/v) porcine follicular fluid (standard), 0.6 mM cysteine, 0.91 mM pyruvate, 75 μg/ml kanamycin, and 1 μg/ml insulin. Immature pig oocytes were matured for 44 h and then oocytes reached metaphase II stage were electrically activated to induce PA. The in vitro culture medium for embryonic development was porcine zygote medium-3 containing 0.3% (w/v) fatty acid-free BSA. When immature oocytes were treated with U0126 during the first 0, 2, 4 h of IVM culture, nuclear maturation was significantly (P < 0.05) increased by the U0126 treatment for 4 h (96.2 ± 1.3%) compared to standard IVM (90.6 ± 2.1%). Cleavage of PA embryos was significantly increased by 4 h- treatment (90.6 ± 2.2%) compared to standard medium (83.9 ± 1.8%). In addition, blastocyst formation of PA embryos was significantly (P < 0.05) increased by the treatment for 4 h (55.8 ± 5.7%) compared to 2 h (38.1 ± 6.1%). The glutathione contents in IVM oocytes were not altered by the U0126 treatments for 0, 2, and 4 h (1.28 ± 0.10, 1.16 ± 0.09, and 1.10 ± 0.09, respectively). Our results demonstrated that 5 μM U0126 treatment during the first 4 h of IVM showed positive effects on nuclear maturation, cleavage, and embryonic development in pigs.