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21.
Background
To infer homology and subsequently gene function, the Smith-Waterman (SW) algorithm is used to find the optimal local alignment between two sequences. When searching sequence databases that may contain hundreds of millions of sequences, this algorithm becomes computationally expensive. 相似文献22.
用透射电镜和扫描电镜观察隆线精子的发生过程及成熟精子的超微结构。隆线精子发生经历精原细胞、精母细胞、精子细胞和成熟精子四个时期。精原细胞核染色质凝集成团,细胞质内有线粒体、粗面内质网分布。精母细胞核染色质分散,不均匀地分布于核中,细胞质内粗面内质网聚集。在精子细胞分化形成精子的早期,细胞纵向拉伸,核物质开始浓缩;中期精子细胞呈明显的长条形,精子细胞逐渐移入精巢管腔中央,外围包裹一厚层精子鞘;后期精子细胞已进入管腔中,核物质呈高度浓缩状,细胞质层较少,精子细胞间通过外围精子鞘相互粘连成片。成熟精子分散在精巢管腔中央,外形呈棒状,一端稍钝,一端稍尖,无鞭毛、棘突等附属物;核内染色质解聚,均匀分布在核中,具双层核膜,细胞质层很少,精子鞘为单层,无法确认顶体端。隆线雄性生殖细胞的结构及其发生过程均较高等甲壳动物简单和原始,但在功能上表现出相对的适应性,使以隆线为代表的枝角类能适应复杂多变的生活环境 相似文献
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转基因植物致敏性的预测方法 总被引:1,自引:0,他引:1
转基因植物的过敏性评估是转基因植物安全性评价中的重要内容,简要介绍了国际上转基因致敏性评估采用的基本策略,重点阐述了氨基酸序列同源性分析技术在致敏性评价中的应用,同时针对当前致敏性评估的局限性,讨论一种致敏性评估的新方法---预测蛋白的免疫原性。通过对两种方法的介绍,旨在说明现代生物信息学在转基因植物致敏性评估中的应用价值。 相似文献
25.
Victor?TS?Chen Chun?Peng Peter?CK?LeungEmail author 《Reproductive biology and endocrinology : RB&E》2003,1(1):29
Activin is known to play an important regulatory role in reproduction, including pregnancy. To further examine the role and signaling mechanism of activin in regulating placental function, the steady-state level of activin type I receptor (ActRI) mRNA in immortalized extravillous trophoblasts (IEVT) cells was measured using competitive PCR (cPCR). An internal standard of ActRI cDNA for cPCR was constructed for the quantification of ActRI mRNA levels in IEVT cells. ActRI mRNA levels were increased in a dose-dependent manner by activin-A with the maximal effect observed at the dose of 10 ng/ml. Time course studies revealed that activin-A had maximal effects on ActRI mRNA levels at 6 hours after treatment. The effects of activin-A on ActRI mRNA levels was blocked by follistatin, an activin binding protein, in a dose-dependent manner. In addition, inhibin-A inhibited basal, as well as activin-A-induced ActRI mRNA levels. These findings provide evidence, for the first time, that activin-A modulates ActRI mRNA levels in human trophoblast cells. 相似文献
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A new variant of glucose phosphate isomerase (GPI), also known as phosphohexose isomerase (PHI), was detected in a primitive pig population. 相似文献
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A statistical analysis of the nucleotide sequence variability in 14
published hepatitis B virus (HBV) genomes was carried out using parametric
and nonparametric methods. A parametric statistical model revealed that the
different regions of the genome differed significantly in their
variability. The conclusion was supported by a nonparametric kernel-density
model of the HBV genome. Genes S, C, and P, region X, the precore region,
and the pre-S2/pre-S1 regions were ranked in order of increasing
variability. In many instances, conserved regions of the genome identified
with sequences of known function in HBV biology. However, other
characterized regions (such as pre-S) showed much variability despite the
involvement of their encoded peptides in specific functions. Point
mutations that may result in the formation of stop codons and amino acid
changes may affect the clinical picture of HBV infection and may be
reflected in atypical serological patterns.
相似文献
29.
An electrophoretic spectra of proteins, extracted with tris-HCI buffer, pH 8.3 are studied. The ditelosomic lines of the Chinese
Spring common wheat cultivar are analysed by the chromosomes of the B genome and of the ditelosomic lines of the same cultivar
by first and third chromosomes of the D genome. It is found that structural genes for the synthesis of components Nos. 7,
8, 9 and 10 are localized in 1BL, 2BS, 4BS and 5B chromosomes respectively. The genetic control of the component No. 3 is
realized by genes, localized in 1BL and 3D chromosomes, while for component No. 2, in the 3D chromosome. 相似文献
30.
Kumaran Kandasamy Sujatha S Mohan Rajesh Raju Shivakumar Keerthikumar Ghantasala S Sameer Kumar Abhilash K Venugopal Deepthi Telikicherla Daniel J Navarro Suresh Mathivanan Christian Pecquet Sashi Kanth Gollapudi Sudhir Gopal Tattikota Shyam Mohan Hariprasad Padhukasahasram Yashwanth Subbannayya Renu Goel Harrys KC Jacob Jun Zhong Raja Sekhar Vishalakshi Nanjappa Lavanya Balakrishnan Roopashree Subbaiah YL Ramachandra Abdul B Rahiman Keshava TS Prasad Jian-Xin Lin Jon CD Houtman Stephen Desiderio Jean-Christophe Renauld Stefan N Constantinescu Osamu Ohara Toshio Hirano Masato Kubo Sujay Singh Purvesh Khatri Sorin Draghici Gary D Bader Chris Sander Warren J Leonard Akhilesh Pandey 《Genome biology》2010,11(1):1-9