• Animal cells and systems
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• 제16권2호
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• pp.104-113
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• 2012

The nucleolus is a distinct nuclear territory involved in the compartmentalization of nuclear functions. There is some evidence of a relationship between nuclear fragmentation during spermatogenesis and chromatoid body (CB) formation. The CB is a typical cytoplasmic organelle of haploid germ cells, and is involved in RNA and protein accumulation for later germ-cell differentiation. The goal of this study was to qualitatively and quantitatively describe the nucleolar cycle during the spermatogenesis of $Phrynops$ $geoffroanus$ (Reptilia Testudines), and compare this nucleolar fragmentation with CB formation in this species through the use of cytochemical and ultrastructural analysis. Qualitative analysis showed a fragmentation of the nuclear material after pachytene of the first meiotic division in the primary spermatocytes. Quantitative analysis of the nucleolar cycle revealed a significant difference in the number of nucleoli and in the size of the nucleolus between spermatogonia and early spermatids. Using ultrastructural analysis, we recorded the beginning of the CB formation process in the cytoplasm of primary spermatocytes at the same time as when nuclear fragmentation occurs. In the cytoplasm of primary spermatocytes, the CB was observed in association with mitochondrial aggregates and the Golgi complex. In the cytoplasm of early spermatids, the CB was observed in association with lipid droplets. In conclusion, our data show that the nucleolus plays a role in the CB formation process. During spermatogenesis of $P.$ $geoffroanus$, the CB is involved in some important biological processes, including acrosome formation and mitochondrial migration to the spermatozoon tail and middle piece region.

• BMB Reports
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• 제41권3호
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• pp.248-253
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• 2008

Stresses and nutritional starvation are two main external signals for the induction of sex pheromones in the fission yeast Schizosaccharomyces pombe. In an attempt to identify the components involved in transduction of starvation signals, we screened 135 temperature-sensitive (ts) mutants and isolated 6 mutants that induced the pheromone even in the presence of a nitrogen source. These mutants exhibited two distict induction phenotypes: pheromone induction at restrictive but not at permissive temperatures; and pheromone induction at both permissive and restrictive temperatures. The times required for the maximum pheromone induction at the restrictive temperature differed slightly in each mutant. In addition to the pheromone induction phenotype, the ts243 and ts304 mutants exhibited cell-division-cycle defects. The ts304 mutant cells showed an abnormal cytoplasmic DAPI staining pattern. The nucleolus of this mutant seemed to be fragmented, a phenomenon which is typically observed in aged yeast cells. The result of our genetic analysis indicated that the pheromone induction mutants belonged to 6 separate complementation groups. We designated these mutants pws1 to pws6.

• Toxicological Research
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• 제17권
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• pp.59-69
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• 2001

Arsenic exposure is associated with several human diseases, including cancers, atherosclerosis, hypertension, and cerebrovascular diseases. In cultured cells, arsenite, an inorganic arsenic com-pound, was demonstrated to interfere with many physiological functions, such as enhancement of oxidative stress, delay of cell cycle progression, and induction of structural and numerical changes of chromosomes. The objective of this study is to investigate the effects of arsenic exposure on gene expression profiles by colorimetric cDNA microarray technique. HFW (normal human diploid skin fibroblasts), CL3 (human lung adenocarcinoma cell line), and HaCaT (immortalized human keratinocyte cell line) were treated with 5 $\mu\textrm{M}$ or 10 $\mu\textrm{M}$ sodium arsenite for 6 or 16 h, respectively. By a dual-color detection system, the expression profile of arsenite-treated cultures was compared to that of control cultures. Several genes expressed differentially were identified on the microarray membranes. For example, MDM2, SWI/SNF, ubiquitin specific protease 4, MAP3K11, RecQ protein-like 5, and Ribosomal protein Ll0a were consistently induced in all three cell types by arsenite, whereas prohibitin, cyclin D1, nucleolar protein 1, PCNA, Nm23, and immediate early protein (ETR101) were apparently inhibited. The present results suggest that arsenite insults altered the expression of several genes participating in cellular responses to DNA damage, stress, transcription, and cell cycle arrest.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2291-2295
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• 2014

Although nucleolar protein nucleostemin (NS) is essential for cell proliferation and early embryogenesis and expression has been observed in some types of human cancer and stem cells, the molecular mechanisms involved in mediation of cell proliferation and cell cycling remains largely elusive. The aim of the present study was to evaluate NS as a potential target for gene therapy of human breast carcinoma by investigating NS gene expression and its effects on SKBR-3 cell proliferation and apoptosis. NS mRNA and protein were both found to be highly expressed in all detected cancer cell lines. The apoptotic rate of the pcDNA3.1-NS-Silencer group ($12.1-15.4{\pm}3.8%$) was significantly higher than those of pcDNA3.1-NS ($7.2-12.0{\pm}1.7%$) and non-transfection groups ($4.1-6.5{\pm}1.8%$, P<0.01). MTT assays showed the knockdown of NS expression reduced the proliferation rate of SKBR-3 cells significantly. Matrigel invasion and wound healing assays indicated that the number of invading cells was significantly decreased in the pcDNA3.1-NS-siRNA group (P<0.01), but there were no significant difference between non-transfected and over-expression groups (P>0.05). Moreover, RNAi-mediated NS down-regulation induced SKBR-3 cell G1 phase arrest, inhibited cell proliferation, and promoted p53 pathway-mediated cell apoptosis in SKBR-3 cells. NS might thus be an important regulator in the G2/M check point of cell cycle, blocking SKBR-3 cell progression through the G1/S phase. On the whole, these results suggest NS might be a tumor suppressor and important therapeutic target in human cancers.

• 한국패류학회지
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• 제1권1호
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• pp.24-50
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• 1985

왜우렁(Parafossarulus manchouricus)은 우리 나라와 중국대륙(中國大陸), 일본(日本), 대만등지(臺灣等地)에 널리 만연(蔓延)되어 있는 간흡충증(肝吸蟲症)(clonorchiasis)의 원인기생충(原因寄生蟲)인 간흡충(肝吸蟲)(Clonorchis sinensis)의 제일중간숙주(第一中間宿主)로서 Bithyniidae 과(科)에 속(屬)하는 담수권패(淡水卷貝)의 일종(一種)이다. 우리나라의 청평(淸平), 진주(晋州), 군산(群山) 및 일본(日本), 대만등지(臺灣等地)에서 채집(採集)된 왜우렁과 공주지역(公州地域)에서 채집(採集)된 Bithynia(Gabbia) misella, 그리고 미국(美國)의 Michigan 호(湖)와 독일(獨逸)의 Bodensee 근역(近域)에서 채집(採集)된 Bithyniatentaculata를 대상(對象)으로 이들의 산난특성(産卵特性), 형태(形態), 세포학적(細胞學的) 특성(特性), 흡충류(吸蟲類)의 자연감염실태(自然感染實態)와 서식지(棲息地)의 생태등(生態等)을 상호비교관안(相互比較觀案)하여 주로 우리나라에 분포(分布)되어 있는 왜우렁의 패류학적(貝類學的) 근거(根據)를 마련하고저 본(本) 연구(硏究)가 수행(遂行)되었다. 왜우렁의 배양(培養)에 있어 중요(重要)한 요소(要素)는 먹이로서 유패(幼貝)인 경우 Navicula나 Gomphonema와 같은 Benthic diatoms가 필수적(必須的)임을 알았고 알에서 부화(孵化)하여 성패(成貝)가 될 때까지는 54日, 그리고 산난(産卵)할때까지는 약(約) 150日이 소요(所要)됨을 알았다. 왜우렁뿐만 아니라 같은 Bithyniidae科에 속(屬)하는 B.(G.) misella나 B. tentaculata도 년(年) 1회(回) 산난(産卵)함을 보았다. 왜우렁의 패곡(貝穀)에는 나선형(螺線形) 육기(陸起)(spiral ridges)가 있음이 타종(他種)과 구별(區別)되는 점(點)이였고 B.(G.) misella의 성패(成貝)의 크기는 7.5mm를 초과하지 않았다. 왜우렁 유패(幼貝)의 주사전자현징경적(走査電子顯徵鏡的) 관내(觀奈)에서 나선형(螺線形) 주름만이 보였을 뿐이여서 Hydrobiidae科에 속(屬)하는 권원류(卷員類)와는 상이(相異)한 형태(形態)를 나타내었다. 왜우렁의 설치(舌齒)는 B. tentaculata와 비숫한 형태(形態)를 보였으나 B.(G.) misella는 cusps가 일반적으로 크고 날카로웠으며 비교(比較)된 삼종(三種) 모두의 치형(齒型)은 2:1:1:1:2이었다. 또한 한국산(韓國産) 왜우렁과 대만산(臺灣産) 왜우렁에 었어 곡고대곡구비(穀高對穀口比)가 서로 통계학적(統計學的)으로 유의(有意)하게 상이(相異)한 것은 지역적환경(地域的環境)의 차리(差異)때문인 것으로 사료(思料)되었다. 왜우렁의 세포분열상(細胞分裂相)은 타종(他種)과 차리(差異)가 없었으나 염색체수(染色體數)는 B. tentaculata와 마찬가지로 n=17이었고 B.(G.) misella는 n=18이었다. 왜우렁의 핵형(核型)은 지역간(地域間)에 그 차리(差異)를 볼 수 없었으며 성염색체(性染色體)는 확인(確認)할 수 없었다. 왜우렁의 간흡충유충감염율(肝吸蟲幼蟲感染率)은 진주산(晋州産) 0.14%, 군산산(群山産) 1.25%이었으나 청평산(淸平産)에서는 0%였으며, 공주산(公州産) B.(G.) misella 亦是 자열감염(自熱感染)을 인정(認定)할 수 없어 간흡충(肝吸蟲)의 중간숙주(中間宿主)가 될 수 없음을 확인(確認)하였다. 왜우렁의 서식처(棲息處)는 수류(水流)가 완만(緩慢)하거나 정체(停滯)될 수계(水系)였으나 비교적(比較的) 오염(汚染)이 적고 용존산소량(溶存酸素量)이 높은 곳에 서식(棲息)하고 있있으며 서식처(棲息處)의 calcium ion양(量)이 타지역(他地域)보다 월등(越等)히 높았음을 알 수 있었다.