江湖阻隔对涨渡湖区鱼类资源的生态影响

长江中游两岸绝大多数通江湖泊自20世纪50年代以来因水利工程阻隔先后失去与长江的联系而产生一系列的生态问题。我们以涨渡湖为例开展江湖阻隔后对单个湖泊鱼类资源所产生的生态影响进行研究,结果表明:江湖阻隔导致湖泊生产经营方式改变,使得野生渔业产量的比例由1949年的95%,降低到2002年的不足5%;江湖阻隔后湖泊鱼类种类由50年代约80种下降到现在的52种,其中,洄游性和流水型鱼类比重由50%下降至不足30%;迷魂阵渔获物在单位产量、个体大小上极显著(p<0.01)地高于通江湖泊,但在物种数和多样性指数上则

人工四倍体鲤鲫成熟卵受精过程的扫描电子显微镜观察

以人工四倍体鲤鲫卵子和普通红鲤精子为材料进行人工受精，在受精后的不同时间以扫描电子显微镜观察卵子对精子的应答反应、受精孔形态、数量与大小以及受精过程等超微结构特征。结果表明，四倍体卵子动物极的卵壳上仅有一个受精孔，但受精孔区域有5—6个似小山丘状的嵴状结构，而鲤却完全没有这种结构。研究证实：四倍体鲤鲫成熟卵属单受精孔、单精受精类型，其特异的嵴状形态结构可作为区分普通鲤的标记表型。

Discovery of a male-biased mutant family and identification of a male-specific SCAR marker in gynogenetic gibel carp Carassius auratus gibelio

Gibel carp ( Carassius auratus gibelio) is a uniquely gynogenetic species with a minor ratio of males in natural habitats, but its male origin and sex determination mechanisms have been unknown. In this study, a male-biased mutant family was discovered from the gynogenetic gibel carp, and a male-specific SCAR marker was identified from the mutant family. Normal spermatogenesis was observed in the male testes by immuno. fluorescence histochemistry. Nearly identical AFLP profiles were observed between males and females, but a male-specific 86 bp AFLP fragment was screened by sex-pool bulked segregant analysis and individual screening. Based on the male-specific AFLP fragment, a total of 579 bp sequences were cloned by genome walking. Subsequently, a male-specific SCAR marker was designed, and the male-specific DNA fragment was confirmed to be steadily transmitted to the next generation and consistently detected only in males. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.

Expression pattern of cellular nucleic acid-binding protein (CNBP) during embryogenesis and spermatogenesis of gibel carp

By differential screening, we cloned the CagCNBP, demonstrated its predominant expression in ovary and testis, and reported its development behavior during folliculogenesis and oogenesis by immunofluorescence localization (Liu and Gui, Gene 365:181-192, 2005), but its developmental behavior during spermatogenesis and its transcript distribution during embryogenesis are not revealed. In the present study, by in situ hybridization, we analyze CagCNBP expression pattern during gibel carp embryogenesis. The CagCNBP transcripts ubiquitously distributed in all embryonic cells in early developmental stage embryos, and peak in midbrain, hindbrain and somites of gibel carp larva during organogenesis. By antibody detection, we reveal CagCNBP protein distribution change during spermatogenesis. The cell-specific distribution of CagCNBP is revealed by immunofluorescence staining, and predominant CagCNBP expression in testis somatic cells and spermatogonia is demonstrated in this paper. For the first time, the CNBP distribution during spermatogenesis in vertebrate has been revealed.

U19/Eaf2 knockout causes lung adenocarcinoma, B-cell lymphoma, hepatocellular carcinoma and prostatic intraepithelial neoplasia

Upregulated gene 19 (U19)/ELL-associated factor 2 (Eaf2) is a potential human tumor suppressor that exhibits frequent allelic loss and downregulation in high-grade prostate cancer. U19/Eaf2, along with its homolog Eaf1, has been reported to regulate transcriptional elongation via interaction with the eleven-nineteen lysine-rich leukemia (ELL) family of proteins. To further explore the tumor-suppressive effects of U19/Eaf2, we constructed and characterized a murine U19/Eaf2-knockout model. Homozygous or heterozygous deletion of U19/Eaf2 resulted in high rates of lung adenocarcinoma, B-cell lymphoma, hepato cellular carcinoma and prostate intraepithelial neoplasia. Within the mouse prostate, U19/Eaf2 defficiency enhanced cell proliferation and increased epithelial cell size. The knockout mice also exhibited cardiac cell hypertrophy. These data indicate a role for U19/Eaf2 in growth suppression and cell size control as well as argue for U19/Eaf2 as a novel tumor suppressor in multiple mouse tissues. The U19/Eaf2 knockout mouse also provides a unique animal model for three important cancers: lung adenocarcinoma, B-cell lymphoma and hepatocellular carcinoma.

Strain status in ZnO film on sapphire substrate with a GaN buffer layer grown by metal-source vapor phase epitaxy

ZnO film of 8 mu m thickness was grown on a sapphire (0 0 1) substrate with a GaN buffer layer by a novel growth technique called metal-source vapor phase epitaxy (MVPE). The surface of ZnO film measured by scanning electron microscope (SEM) is smooth and shows many regular hexagonal features. The full width at half maximum (FWHM) of ZnO(0 0 2) and (1 0 2) omega-scan rocking curves are 119 and 202 arcsec, corresponding a high crystal quality. The status of the strain in ZnO thick film was particularly analyzed by X-ray diffraction (XRD) omega-20 scanning. The results show that the strain in ZnO film is compressive, which is also supported by Raman scattering spectroscopy. The compressive strain can solve the cracking problem in the quick growth of ZnO thick film. (c) 2008 Elsevier Ltd. All rights reserved.

热氧化方法改善硅干法刻蚀波导的表面粗糙度

提出了一种热氧化的方法来改善干法刻蚀硅波导的表面质量.通过Suprem二维工艺模拟程序对氧化过程的物理模型进行了分析.用实验证实了该方法的可行性并与模拟结果进行了比较.实验中将硅波导的表面粗糙度由65.4nm降低到了8.8nm.另外讨论了分次氧化方法的利弊.

不同施肥制度对作物产量及肥料贡献率的影响

通过17年的长期定位肥料试验,研究了不同施肥制度对作物产量及肥料贡献率的影响,结果表明:化肥N、P、K的施用均能明显提高作物产量,其增产率分别为32.10%、15.06%、10.95%;循环回田的农家肥养分对作物增产有明显的残效叠加作用,且具有良好的稳产作用,可以满足作物对不同气候年景的适应性。在本试验中,若将保持养分循环再利用基础上施用NPK化肥视为最佳施肥制度,则在保持其他农业技术不变条件下,最大施肥贡献率为0.44。在下辽河平原土壤、气候和生产力水平等条件下,为保证作物持续高产,应同时施用化肥和循环肥。