Programmed cell death (PCD) is thought as a well-controlled process by which unwanted cells are selectively eliminated. During the last decade many researches have elucidated molecules and their interactions involved in cell death by using largely in vitro induction of cell death or survival signals in a more defined manner, While these critical information and novel findings provide us with clearer understanding of mechanisms underlying cell death, it does by no means explain how PCD occurs and which cells or tissues are affected during normal embryonic development in vivo. In this study, we used zebrafish to examine whether the PCD is occurring selectively or randomly in developing embryos by whole mount in situ TUNEL analysis with specific markers for neural cells. The result revealed that the degree and distribution of TUNEL staining varied considerably throughout gastrulation stage, and there was also a number of TUNEL-negative embryos. Most of TUNEL-positive cells were scattered randomly throughout the blastoderm. During the gastrulation stage about 75 % of the embryos analyzed exhibited more than 5 TUNEL-positive cells. As the dorsal epiblast begins to thicken rather abruptly near the end of gastrulation, TUNEL-positive cells were mainly located along the dorsal side. Although there were some variations in TUNEL staining during segmentation and pharyngeal stages, TUNEL staining continued to be localized to the central nervous system, and was also detected in the sensory organs, trigeminal ganglions, and the primary sensory neurons. High levels of the cell death in developing brain between 20-somite and prim-6 stages are thought to play a role in the morphogenesis and organization of the brain. At prim-16 stage, cell death is considerably reduced in the brain region. Dying cells are mainly localized to the prospective brain region where ectodermal cells are about to initiate neurogenesis. As development progressed, high levels and more reproducible patterns of cell death were observed in the developing nervous system. Intensive TUNEL staining was restricted to the trigeminal ganglions, the primary sensory neurons, and sensory organs, such as olfactory pits and otic vesicles. Thus, PCD patterning in zebrafish embryos occurs randomly at early stages and becomes restricted to certain region of the embryos. The spatio-temporal pattern of PCD during the early embryonic development in zebrafish will provide basic information for further studies to elucidate genes involved in. regulation of PCD largely unknown in vivo during vertebrate embryogenesis.

본 연구의 목적은 안성천 상류 공도유역(366.5km²)을 대상으로 SWAT 모형을 이용하여 미래 기후변화 평가에 있어, 미래의 토지이용변화를 동시에 고려하면 수문학적 거동에 얼마나 영향을 주는지를 분석하고자 하였다. 미래기후변화 시나리오는 HadGEM3-RA의 RCP 4.5와 8.5 시나리오를 이용하여 2030s (2020-2039)과 2050s (2040-2059) 기간으로 나누어 적용하였으며, 토지이용변화는 도시성장 시나리오에 따른 회귀모형 기반의 CLUE-s 모델을 이용하였다. 기준년(1976-2005) 대비 미래 강수량은 RCP 4.5에서 2030s에 최대 5.7%의 감소, 2050s에는 최대 18.5% 증가하였고, 미래 기온은 2030s RCP 4.5에서 최대 1.8°C, 2050s RCP 8.5에서 최대 2.6°C 증가하였다. 미래 토지이용은 2050년 도시지역이 58.6% (29.0 km²에서 46.0 km²) 증가하는 것으로 예측되었다. SWAT 수문 검보정은 14년(2002-2015) 동안의 공도관측소 일유량 자료를 이용하였으며, 저유량 모델효율의 향상을 위하여 2014-2015년 연속 가뭄년을 대상으로 보정을 실시한 결과, 하천유량(Q)과 1/Q을 대상으로Nash-Sutcliffe 모델효율은 각각 0.86과 0.76이었다. 미래 기후변화 시나리오만을 적용한 결과, 하천유출량이 2030s RCP 4.5에서 최대 24.2% 감소하다가 2050s RCP 4.5에서 최대 10.9% 증가하는 변화를 보여주었다. 한편, 기후변화와 더불어 미래의 토지이용변화를 함께 고려한 경우는 하천유출량이 2030s RCP 4.5에서 최대 14.9% 감소, 2050s RCP 4.5에서 최대 19.5% 증가하는 변화를 보여주어, 미래 기후변화에 따른 유역의 수문평가 시, 도시성장이 기대되는 유역 등 미래의 토지이용변화가 클 가능성이 있는 유역에 대해서는 토지이용변화 요소를 고려할 필요가 있다고 생각된다.