普通野生稻线粒体蛋白质编码基因密码子使用偏好性的分析

以普通野生稻(Oryza rufipogon Griff.)线粒体基因组为对象,分析其蛋白质编码基因的密码子使用特征及与亚洲栽培稻(O. sativa L.)的差异,探讨其密码子偏性形成的影响因素和进化过程。结果显示:普通野生稻线粒体基因组编码序列第1、第2和第3位碱基的GC含量依次为49.18%、42.67%和40.86%;有效密码子数(Nc)分布于45.32～61.00之间,其密码子偏性较弱; Nc值仅与GC_3呈显著相关,密码子第3位的碱基组成对密码子偏性影响较大;第1向量轴上显示9.91%的差异,其与GC_3s、Nc、密码子偏好指数(CBI)和最优密码子使用频率(Fop)的相关性均达到显著水平;而GC_3和GC₁₂的相关性未达到显著水平。因此,普通野生稻线粒体基因组密码子的使用偏性主要受自然选择压力影响而形成。本研究确定了21个普通野生稻线粒体基因组的最优密码子,大多以A或T结尾,与叶绿体密码子具有趋同进化,但是与核基因组具有不同的偏好性。同义密码子相对使用度(RSCU)、PR2偏倚分析和中性绘图分析显示,普通野生稻线粒体基因功能和其密码子使用密切相关,且线粒体密码子使用在普通野生稻、粳稻(O. sativa L. subsp. japonica Kato)和籼稻(O. sativa L. subsp.indica Kato)内具有同质性。     

Conversion therapy of intermediate and advanced hepatocellular carcinoma using superstable homogeneous iodinated formulation technology

Science China Life Sciences -     

Realized niche shift associated with Galinsoga quadriradiata (Asteraceae) invasion in China

粗毛牛膝菊在中国的入侵与生态位漂移有关 在外来物种入侵和扩散过程中,生态位的漂移可能起到了重要作用。粗毛牛膝菊(Galinsoga quadriradiata) 在中国已造成了较为严重的入侵,占据了许多与其原产地不同的气候区。为此,本研究力图揭示粗毛牛膝菊入侵过程中的气候生态位漂移,分析其在该物种入 侵中国过程中可能发挥的作用。本研究结合粗毛牛膝菊原 产地和入侵地的分布点与气候数据, 采用Maxent模型预测了其在中国潜在的分布,并采用主成分分析的方法评估 了在入侵中国过程中粗毛牛膝菊气候生态位的漂移。模型结果显示,该物种原产地种群和入侵地种群之间只 有32.7%的生态位重叠,两个种群的生态位相似性较低(Schoener's D = 0.093, P < 0.005),这暗示了在其入侵过程中发生了生态位漂移。相比于其原产地种群,其在中国的入侵种群气候生态位的整体范围和中心都明 显地漂移向了温度更低、降水更少的区域;中国南方大部分区域属于粗毛牛膝菊的稳定适生区,而位于入侵 前沿的北方地区则存在局域适应和潜在拓殖区域。这些研究结果说明,粗毛牛膝菊在中国的入侵种群仍处于准平衡阶段,未来有可能继续向新的适生区扩散入侵,其生态位的变化有力地解释了为什么该物种在中国的入侵性强、危害范围大。     

Interaction of rice dwarf virus outer capsid P8 protein with rice glycolate oxidase mediates relocalization of P8

Yeast two-hybrid and coimmunoprecipitation assays indicated that P8, an outer capsid protein of Rice dwarf phytoreovirus (RDV), interacts with rice glycolate oxidase (GOX), a typical enzyme of peroxisomes. Confocal immunofluorescence microscopy revealed that P8 was colocalized with GOX in peroxisomes. Time course analysis demonstrated that the localization of P8 in Spodoptera frugiperda cells changed from diffuse to discrete, punctuate inclusions during expression from 24 to 48 h post inoculation. Coexpression of GOX with P8 may target P8 into peroxisomes, which serve as replication sites for a number of viruses. Therefore, we conclude that the interaction of P8 with the GOX of host cells leads to translocation of P8 into peroxisomes and we further propose that the interaction between P8 and GOX may play important roles in RDV targeting into the replication site of host cells. Our findings have broad significance in studying the mechanisms whereby viruses target appropriate replication sites and begin their replication.     

Effects of Elevated Carbon Dioxide on the Growth and Foliar Chemistry of Transgenic Bt Cotton

A field study was carried out to quantify plant growth and the foliar chemistry of transgenic Bacillus thuringiensis （Bt） cotton （cv. GK-12） exposed to ambient CO2 and elevated （double-ambient） CO2 for different lengths of time （1, 2 and 3 months） in 2004 and 2005. The results indicated that CO2 levels significantly affected plant height, leaf area per plant and leaf chemistry of transgenic Bt cotton. Significantly, higher plant height and leaf area per plant were observed after cotton plants that were grown in elevated CO2 were compared with plants grown in ambient CO2 for 1, 2 and 3 months in the investigation. Simultaneously, significant interaction between CO2 level x investigating year was observed in leaf area per plant. Moreover, foliar total amino acids were increased by 14%, 13%, 11% and 12%, 14%, 10% in transgenic Bt cotton after exposed to elevated CO2 for 1, 2 or 3 months compared with ambient CO2 in 2004 and 2005, respectively. Condensed tannin occurrence increased by 17%, 11%, 9% in 2004 and 12%, 11%, 9% in 2005 in transgenic Bt cotton after being exposed to elevated CO2 for 1, 2 or 3 months compared with ambient CO2 for the same time. However, Bt toxin decreased by 3.0%, 2.9%, 3.1% and 2.4%, 2.5%, 2.9% in transgenic Bt cotton after exposed to elevated CO2 for 1, 2 or 3months compared with ambient CO2 for same time in 2004 and 2005, respectively. Furthermore, there was prominent interaction on the foliar total amino acids between the CO2 level and the time of cotton plant being exposed to elevated CO2. It is presumed that elevated CO2 can alter the plant growth and hence ultimately the phenotype allocation to foliar chemistical components of transgenic Bt cotton, which may in turn, affect the plant-herbivore interactions.     

猪肌肉组织Col3a1基因表达的发育性变化及其对肌内胶原特性的影响

以30—90妇体重莱芜猪和40—100kg体重鲁莱黑猪共84头去势公猪为试验对象（每组6头）,采用相对定量RT-PCR方法,以β-actin作为内标,研究肌肉中编码Ⅲ型胶原的Col3al基因表达的发育性变化及其对肌肉中胶原蛋白含量和性质（溶解度）的影响。结果表明：研究的两个品种猪肌肉中Col3al基因表达的发育性变化基本一致,即随体重的增加,肌肉中Col3al mRNA表达呈逐渐增加趋势,但莱芜猪和鲁莱黑猪分别在70妇和80妇体重组表达量略有下降。总体上莱芜猪肌肉组织Col3al mRNA表达丰度显著高于鲁莱黑猪（P〈0．05）。相关分析表明,莱芜猪肌肉组织Col3al mRNA表达的发育性变化与总胶原和不溶性胶原含量呈极显著正相关（P〈0．01）,与胶原溶解度呈极显著负相关（P〈0．01）。鲁莱黑猪肌肉组织Col3al mRNA表达的发育性变化与不溶性胶原和胶原溶解度分别呈显著正相关和负相关妒〈0．05）。研究结果提示：猪肌肉组织中Col3al基因表达具有明显的体重发育和品种特征,其mRNA表达对于肌内胶原的含量和性质有重要影响。     

Analysis of Protein Three-Dimension Structure Using Amino Acids Depths

The issue of amino acid depth in proteins gives important insights to our understanding of protein’s three-dimensional structure. There has already been much research done in mathematical and statistical sciences regarding the general definitions, properties and algorithms describing the particle depth of spatially extended systems. We constructed a method of calculating the amino acids depths and applied it to a set of 527 protein structures. We propose the introduction of amino acid depth tendency factors for three-dimensional structures of proteins. The depth tendency factors relate not only to the hydrophobicity indices but also to the electrostatic charge. We found a relationship between the protein size and the number of residues using the distance between the deepest residue and surface residues. We made a prediction regarding the number of residues on the surface of a protein, the deepest amino acid, and the average depth, all of which are fitted well to a linear functional relationship with the length of the protein. Finally, we have predicted the depths of multiple peptides in protein’s three-dimension structure. Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users.     

The effects of delayed activation and MG132 treatment on nuclear remodeling and preimplantation development of embryos cloned by electrofusion are correlated with the age of recipient cytoplasts

The electrofusion method, used extensively in livestock cloning, cannot be used in mice, because it is believed that the mouse oocytes are more susceptible to detrimental effects of electrical stimulus than oocytes from other species. Reports on whether a delayed activation after electrofusion and a premature chromosome condensation (PCC) is essential for efficient cloning are inconclusive. To address these issues, effects of pulsing on activation and MPF activity of nonenucleated oocytes and effects of delayed activation and MG132 treatment on donor nuclear PCC and preimplantation development of embryos cloned by electrofusion or nuclear injection were compared between different cytoplast ages in mice and goats. The results indicated that the use of oocytes collected early after donor stimulation would make it possible to conduct somatic cell nuclear transfer in mice by electrofusion. Whether a delayed activation is essential was dependent upon the age, or rather, the level, of MPF activity of the cytoplasts at the time of electrofusion, as was the requirement for MG132 treatment. The competence for blastocyst formation of cloned embryos was highly correlated with the level of donor nuclear PCC in recipient cytoplasts. The nuclear injection technique was more adaptable to older cytoplast ages, and hence less dependent on drugs for inhibition of MPF inactivation, compared to electrofusion.